Neurotransmitter alteration is a mechanism of neural dysfunction that occurs after concussion and contributes to the sometimes-catastrophic long-term consequences. This rat model combines microdialysis, allowing in vivo neurotransmitter quantification, with a weight-drop technique exerting rapid acceleration and deceleration of the head and torso, an important factor of human craniocerebral trauma.
Persistent cognitive and motor symptoms are known consequences of concussions/mild traumatic brain injury (mTBIs) that can be partly attributable to altered neurotransmission. Indeed, cerebral microdialysis studies in rodents have demonstrated an excessive extracellular glutamate release in the hippocampus within the first 10 min following trauma. Microdialysis offers the clear advantage of in vivo neurotransmitter continuous sampling while not having to sacrifice the animal. In addition to the aforementioned technique, a closed head injury model that exerts rapid acceleration and deceleration of the head and torso is needed, as such a factor is not available in many other animal models. The Wayne State weight-drop model mimics this essential component of human craniocerebral trauma, allowing the induction of an impact on the head of an unrestrained rodent with a falling weight. Our novel and translational rat model combines cerebral microdialysis with the Wayne State weight-drop model to study, in lightly anesthetized and unrestrained adult rats, the acute changes in extracellular neurotransmitter levels following concussion. In this protocol, the microdialysis probe was inserted inside the hippocampus as region of interest, and was left inserted in the brain at impact. There is a high density of terminals and receptors in the hippocampus, making it a relevant region to document altered neurotransmission following concussion. When applied to adult Sprague-Dawley rats, our combined model induced increases in hippocampal extracellular glutamate concentrations within the first 10 min, consistent with the previously reported post-concussion symptomology. This combined weight-drop model provides a reliable tool for researchers to study early therapeutic responses to concussions in addition to repetitive brain injury, since this protocol induces a closed-head mild trauma.
The purpose of this method is to provide researchers with a reliable tool that faithfully reproduces the biomechanics of human craniocerebral trauma while allowing longitudinal characterization of the molecular effects of concussions/mild traumatic brain injury (mTBIs). This method combines cerebral microdialysis with the Wayne State weight-drop model to document, in lightly anesthetized and unrestrained adult rats, the acute changes in extracellular neurotransmitter levels following concussion. With this minimally-invasive method, neurotransmitters such as glutamate, GABA, taurine, glycine and serine can be rapidly and continuously quantified following trauma, in vivo, while not having to sacrifice the animal.
Concussion/mTBI is a pathophysiological disruption that affect brain functioning caused by an external force mechanism. Concussion/mTBI is the most common form of traumatic brain injury, accounting for 70-90% of cases1. Most of the acute functional disruptions following a concussion can be attributed to a primary and a secondary brain injury2,3: (1) the primary brain injury is induced by the rapid acceleration and deceleration of the head and torso which damages brain tissues by compression followed by the stretching and shearing of axons during the backlash4,5,6 and (2) the secondary brain injury is the indirect cellular response to the trauma. It takes place hours and days after the primary brain injury and plays an important role in the motor and cognitive impairment observed over time. Many of the symptoms can be attributed to altered neurotransmission such as the previously demonstrated excessive extracellular glutamate release in the first 10 min following injury7,8,9. Given its high density of terminals and receptors, the hippocampus is a brain structure particularly vulnerable to this excitotoxic response following injury. Being heavily involved in cognitive function10,11, studies in rodents reported that hippocampal damage associated with concussion can lead to impairments in fear conditioning and learning spatial memory12,13. The primary objective of this methodology was to work out a rat model of concussion/mTBI, using the Wayne State closed head weight-drop procedure to faithfully reproduce the mechanisms of the primary brain injury, and incorporate cerebral microdialysis to study in vivo, the acute extracellular neurotransmitter changes due to the secondary brain injury following a concussion. Concentrations of extracellular glutamate and GABA were measured in the hippocampus to act as representative results of our method.
Previous rodent studies have combined microdialysis and other models of injury, such as the open-skull weight drop and controlled cortical impact, to demonstrate the acute changes in extracellular neurotransmitter levels following an injury of varying severity degrees14,15,16,17. However, in addition to the high degrees of variability, the translational value of models like the open-skull weight drop and controlled cortical impact is hampered by an inherent lack of ecological validity due to 2 factors: (1) these models induce injuries much more severe than sport-related concussions suffered in humans, involving direct brain loading and (2) these models necessitate a craniectomy or a craniotomy, the head of the rodent being completely restrained in a stereotaxic frame, impeding the rapid acceleration and deceleration of the head and torso, thus poorly reproducing the biomechanics of concussion.
Microdialysis is a minimally-invasive method which offers the clear advantage of sampling neurotransmitters such as glutamate, GABA, taurine, glycine and serine, in vivo and continuously following trauma, while not having to sacrifice the animal. In addition to the advantages offered by microdialysis, the Wayne State University developed a closed-skull weight-drop model (as opposed to open-skull from other models), which allows the induction of a mTBI on a lightly anesthetized and unrestrained rodent, thus allowing the rapid acceleration and deceleration of the head and torso18. As mentioned previously, the acceleration and deceleration of the head and torso is a core biomechanical feature of sport-related concussions seen in humans that previous rodent mTBI models have failed to address. The weight-drop procedure can be done very quickly and does not require any prior surgery or scalp incision. Following induction of the concussion, rodents recover the righting reflex almost spontaneously and do not experience paralysis, seizures or respiratory distress after a single impact. Intracranial bleedings and skull fractures are rare, and only minor deficits in motor coordination have been reported in rodents. This rat model is easy-to-use, inexpensive and facilitates the quantification of neurotransmitters released in the acute phase following a concussion without removing the microdialysis probe during the impact.
Our rat model combining microdialysis and concussion is appropriate for researchers seeking to characterize longitudinally the molecular effects of concussion and could be used in a wide variety of therapeutical studies. Indeed, despite several years of research and an overwhelming need, no drug to prevent the long-term effects of concussions has passed the clinical trial phase19. One of the potential reasons for these failures could be the use of animal models that do not faithfully reproduce the traumatic biomechanical forces of concussions as experienced by humans. The method presented here meets the definition of human concussions which specifies that the primary brain injury is induced by a blunt impact as well as rapid acceleration and deceleration of the head and torso2,3.
Furthermore, our combined model is appropriate for researchers studying the effects of repeated mild traumatic brain injury (rmTBI) since one of its key characteristics that sets it apart from other animal models of concussion is that it makes it possible to induce repeated, mild injuries to the same case18. In humans, rmTBI is associated with more severe post-traumatic symptoms, longer recovery times, and aggravated motor and cognitive impairments that tend to spread over time20,21. Other relevant animal models have also made it possible to better understand the post-traumatic pathophysiology of rmTBI22,23,24,25,26,27. Increased brain vulnerability has been demonstrated in rodents after a minimum of 5 mTBI at 24 h intervals. Neuroinflammation increases with the number of mTBI experienced and markers of neurodegeneration appear28. Repeated mTBI would prevent the transition of microglia from a proinflammatory mode to a normal mode of recovery, resulting in prolonged excitotoxic activity and activation of neurodegenerative mechanisms 29. With our model, rats could be exposed to 1 impact per day over the period of 1 week for a total of 5 exposures. Given the simplicity of this animal model, it could facilitate the characterization of the cumulative effects of the acute indiscriminate neurotransmitter release arising immediately after a mTBI.
This model also allows animals to be readily exposed to 2 impacts per day, making it possible to study even more severe conditions such as when an athlete receives another traumatic impact within a short time from the first blow30. As demonstrated in a previous study31, the timing of a second blow to the head can dramatically affect vascular and axonal damage. The closer the second blow is to the first blow, the more damaging the consequences. This model is appropriate for investigating how this particular condition affects extracellular neurotransmitter release.
In this method, the hippocampus was used as region of interest due to its relevancy in concussion research but microdialysis samples can be collected from other regions of interest as well. However, any other brain region has to be considered on account of the space left by the impact site from the guide cannula, including the dental cement surrounding it, can take up a considerable amount of space on the rat’s head. In addition to this, the microdialysis parameters presented in this method such as the membrane’s molecular weight cut-off and active length, the sampling time intervals and the flow rate can be adjusted according to the type of molecule studied. The efficient collection of pro-inflammatory cytokines involved in concussions, for example, would require a membrane with a much larger pore size.
The animal protocol for this project obtained the approval from the Animal Care Committee of the Hopital du Sacre-Cœur de Montreal in compliance with the guidelines of the Canadian Council on Animal Care.
NOTE: A schematic outline of the research protocol is presented in Figure 1.
1. Animal Preparation
2. Microdialysis Guide Cannula Implantation Surgery
3. Microdialysis Procedure
4. Concussion Apparatus Installation
5. Concussion Induction
6. Sham Induction
7. High-performance Liquid Chromatography
8. Histology
Using our model of concussion which combines force and rotation with in vivo cerebral microdialysis, the acute extracellular glutamate and GABA changes over time following a concussion or sham injury were investigated in 21 male, adult, Sprague-Dawley rats by the implantation of a guide cannula in the CA1 region of the hippocampus.
Histological verification of probe placement and injury
No morphological changes such as massive intracerebral hemorrhages or contusions were reported following the histological verification of hippocampus tissue damage on sections stained with cresyl violet. Guide cannula implantation and microdialysis probe insertion induced minor and similar damages between injured and sham cases. Moreover, not removing the probe right before sham injury or concussion induction did not yield any distinguishable hippocampus tissue damage as seen under a microscope (Figure 2B,C, respectively), with the membrane of the probe still intact afterwards (Figure 2D,E). Concussion and sham injury brains perfused with paraformaldehyde (4%) 1 month following microdialysis procedures are indistinguishable upon visual inspection (Figure 2F,G).
Righting reflex time
Animals from the injured group had a significantly increased righting time on average versus sham cases (Student’s t-test, p = 0.042801) (Figure 4) and appeared stunned upon regaining consciousness. Of the 10 cases from the concussion group, a single animal showed minor signs of bleeding under the impact site following the weight-drop. No other signs of skull fracture or intracranial bleeding were observed.
In vivo cerebral microdialysis
To act as representative results of our method, fifteen 10 μL samples of dialysate were extracted from the hippocampus, in vivo, at intervals of 10 min and a flow rate of 1 μL/min. Extracellular levels of glutamate and GABA were measured from 6 samples during baseline (60 min) and from 9 samples following induction of sham injury or concussion (90 min).
Extracellular concentrations of glutamate
Significant increases in extracellular glutamate concentrations were observed in the CA1 region of the hippocampus during the first 10 min following induction of trauma compared to sham injury (Mann-Whitney U Test, p = 0.009175) (Figure 5). No other difference in glutamate concentrations were observed between groups at any other time point.
Extracellular concentrations of GABA
No significant change in GABA concentrations were observed in the CA1 region of the hippocampus during the first 10 min following induction of trauma compared to sham injury (Mann-Whitney U Test, p = 0.943861) (Figure 6). There was no other significant difference in GABA concentrations at any other time point between concussion cases and sham injury cases.
FIGURE LEGENDS:
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Figure 1: Schematic outline of the research protocol. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Figure 2: Histological verification of probe placement and injury. (A) Coronal view of the microdialysis probe and guide cannula placement site in the hippocampus using the stereotaxic atlas of Paxinos and Watson. (B) Representative photomicrograph of hippocampus tissue damage (cresyl violet) produced by a microdialysis probe and guide cannula from a sham injury case. (C) Representative photomicrograph of hippocampus tissue damage (cresyl violet) produced by a microdialysis probe and guide cannula from a concussion case. (D) Representative photomicrograph of a microdialysis probe before induction of concussion. (E) Representative photomicrograph of a microdialysis probe after induction of concussion. The membrane is still intact. (F-G). Representative photomicrograph of a sham (F) and concussion (G) injured brain following perfusion with 4% paraformaldehyde at 1-month after sham injury or concussion procedure. Upon visual inspection, the 2 brains are indistinguishable. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Figure 3: Concussion apparatus and microdialysis instruments essential components depictions. (A) A photograph of the entire assembly comprised of a vertical polyvinyl chloride (PVC) guide tube for the falling weight situated above the rat stage, Plexiglas frame, foam cushion, computer-controlled microinfusion pump, gastight syringes, liquid swivels, and side-by-side fused silica inlet-outlet lines. (B) Schematic representation of the Plexiglas frame and foam cushion with all pertinent dimensions. (C) A photograph of the slotted piece of aluminum foil that serves as the rat stage above the foam cushion. (D) A photograph showing the positioning of the rat on the stage immediately prior to head impact by the falling weight. (E) A photograph showing the rat after head impact, illustrating the 180° horizontal rotation of the body of the rat after the head impact and ensuing acceleration and rotation. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Figure 4: Righting time. Histogram representations of the time taken by rats to wake from the anesthetic and flip from the supine position to the prone position or begin walking following concussion (red diamonds, n = 10) or sham injury (blue squares, n = 11). Rats from the concussion group took significantly longer to right themselves compared to the sham injury group. Mean values are represented as a horizontal line in each graph. * p < 0.05, ** p < 0.01, *** p < 0.001. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Figure 5: Extracellular concentrations of glutamate. Mean extracellular concentrations of glutamate (μg/mL) measured by microdialysis in the hippocampus during baseline (60 min) and after concussion (red diamonds, n = 10) or sham injury (blue squares, n = 11) conditions (90 min). Error bars represent the standard error of mean. * P < 0.05, ** P < 0.01, *** P < 0.001. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Figure 6: Extracellular concentrations of GABA. Mean extracellular concentrations of GABA (μg/mL) measured by microdialysis in the hippocampus during baseline (60 min) and after concussion (red diamonds, n = 10) or sham injury (blue squares, n = 11) conditions (90 min). Error bars represent the standard error of mean. * P < 0.05, ** P < 0.01, *** P < 0.001. This figure has been modified from IO Masse 2018. Please click here to view a larger version of this figure.
Critical steps in the protocol
For the generation of reliable results, critical steps in this protocol require particular attention. During the cannula implantation surgery, avoid using more cement than necessary, especially when it is very liquid as to prevent spilling over the impact site. To avoid blocking the implantation site, use an obturator that is the same length as the cannula. During the microdialysis procedure, insert the probe slowly into the cannula and make sure that it is inserted completely for dialysate sampling. Before the concussion induction, make sure that the aluminum sheet is properly slotted with a sharp razor blade. Otherwise, the impact from the brass weight won’t be sufficient to rip the aluminum sheet and the rat will remain chest down instead of undergoing an 180° rotation and landing on its back. If this is the case, injuries induced will result from the blunt impact, not unlike what is seen in the open-skull weight drop models and be significantly more severe. During the concussion induction, avoid impacting the cannula with the weight as this would generate critical damage to the skull of the rat. It is highly recommended to work in teams of 2 to restrict manipulation errors during the experiment.
Modifications and troubleshooting
During the microdialysis procedure, flow should be constant and yield a volume appropriate to the rate of perfusion, once the probe is linked to the pump. Lower volumes can indicate the presence of clogging in the membrane of the probe or air bubbles in the lines. In the case of clogging, the probe should be discarded and replaced. However, air bubbles can be ejected by circulating ACSF in the lines. If there is no clogging or air bubbles noted and there is still no flow, a small part of the outflow tube nearest to the end can be cut.
Limitations of the method
Other studies using the Wayne State University weight-drop have evaluated some fundamental structural and molecular changes18. However, a more extensive investigation would maintain the legitimacy of this procedure. Information regarding the biological and neuroanatomical changes that take place at epigenetic and cellular levels would further solidify the reliable and translational value of our method. Furthermore, evaluation of cognitive function is a reliable measure of outcome related to mTBI in rodent models33. While the time-to-right was measured in this protocol and was significantly delayed in injured cases compared to sham cases, studies in the future should concentrate on methodically measuring cognitive function following trauma induction in rodents.
Significance of the method with respect to existing/alternative methods.
The main significance of the method is twofold: Firstly, it allows the successful induction of a concussion with the Wayne State University procedure, which allows rapid acceleration and deceleration of the head and torso. With this method, serious injury outcomes such as cardiorespiratory arrests, skull fracture, high mortality and signs of visible cerebral contusions at the impact site were avoided. Secondly, this microdialysis technique successfully replicated the previously demonstrated the acute and short-lived extracellular glutamate release taking place within the first 10 min following trauma induction14,16. Moreover, keeping the probe inserted throughout the whole procedure significantly reduces the likelihood of inducing damage to the mTBI-sensitive blood-brain barrier linked to repeated microdialysis probe insertion34.
Future applications or directions of the method.
Given the easy-to-use aspects of the Wayne State University weight-drop procedure and the acute extracellular neurotransmitter level changes measured by microdialysis, our rat model combining microdialysis and concussion provides researchers with a reliable tool to faithfully reproduces the biomechanics of human craniocerebral trauma and longitudinally characterize the molecular effects of concussions. Our rat model could also be used in a wide variety of therapeutical studies as it offers a valuable opportunity to study the mechanism and efficacy of pharmacologic agents in vivo, continuously and without having to sacrifice the animal. Furthermore, the availability of a rat model such as the one presented here could greatly facilitate the better understanding of the relationship between the neurotransmitter imbalances and the behavioral consequences of concussions.
The authors have nothing to disclose.
We are grateful to Louis Chiocchio for animal care and maintenance, Morgane Regniez for assistance with the intracardiac perfusion procedure, and David Castonguay for assistance with the cryostat. This work was supported by the Caroline Durand Foundation Chair in acute traumatology of the Universite de Montreal awarded to LDB.
Animal Preparation | |||
Sprague Dawley Rats | Charles River Laboratories | SAS SD 40 | |
Name | Company | Catalog Number | Comments |
Microdialysis Guide Cannula Implantation Surgery | |||
Ketamine Hydrochloride (100 mg/ml) | Bioniche | 1989529 | |
Xylazine Hydrochloride (100 mg/ml) | Bimeda | 8XYL004C | |
Solution of Chlorhexidine Gluconate 2% and Isopropyl Alcohol 2% | Carefusion | 260100C | |
Lidocaine Hydrochloride | Alveda Pharma | 0122AG01 | |
Bupivacaine Hydrochloride | Hospira | 1559 | |
Ophthalmic Ointment | Baussh and Lomb inc. | 2125706 | |
Stereotaxic Frame | Stoelting | 51600 | |
Stereotaxic Cannula Holder Arm | Harvard Apparatus | 72-4837 | |
Drill | Dremel | 8050-N/18 | |
Suture Thread Coated Vicryl Rapide 4-0 | Ethicon | VR2297 | |
Dental Acrylic Cement | Harvard Apparatus | 72-6906 | |
Screws | JI Morris Company | P0090CE125 | |
Isoflurane | Baxter | CA2L9100 | |
Cannula Gauge 20 10.55mm | HRS Scientific | C311G/SPC | |
Dummy-Cannula 10.55mm | HRS Scientific | C311DC/1/SPC | |
Name | Company | Catalog Number | Comments |
Microdialysis Procedure | |||
CMA 402 Syringe Pump | Harvard Apparatus Canada | CMA-8003110 | |
Microsyringe 2.5ml Glass | Harvard Apparatus Canada | CMA-8309021 | |
Syringe Clip Medium For 1-2.5ml | Harvard Apparatus Canada | CMA-3408310 | |
Low-Torque Dual Channel Quartz-Lined Swivel | Instech Laboratories Inc. | 375/D/22QM | |
GSC Cast Iron Support Ring Stand | Fisher Scientifique | S13748 | |
Fisherbrand Castaloy Adjustable-Angle Clamps | Fisher Scientifique | 05769Q | |
NaHCO3 Sodium Bicarbonate | Sigma-Aldrich Canada | S5761-500G | For Artificial Cerebrospinal Fluid (aCSF) |
MgCl2 Magnesium Chloride | Sigma-Aldrich Canada | M8266-100G | For Artificial Cerebrospinal Fluid (aCSF) |
NaCl Sodium Chloride | Sigma-Aldrich Canada | S7653-1KG | For Artificial Cerebrospinal Fluid (aCSF) |
L-Ascorbic Acid | Sigma-Aldrich Canada | A5960-25G | For Artificial Cerebrospinal Fluid (aCSF) |
KCl Potassium Chloride | Sigma-Aldrich Canada | P9333-500G | For Artificial Cerebrospinal Fluid (aCSF) |
NaH2PO4 Sodium Phosphate Monobasic | Sigma-Aldrich Canada | S0751-1KG | For Artificial Cerebrospinal Fluid (aCSF) |
CaCl2 Calcium Chloride | Sigma-Aldrich Canada | 383147-100G | For Artificial Cerebrospinal Fluid (aCSF) |
Lighter | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Epoxy Glue | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Super Glue Gel | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Heat Shrink Tube 0.063" Inner Diameter Gardner Bender | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Cut-Off Wheels Dremel #409 | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
BD Needle 26 Gauge 0.5 Inch PrecisionGlide Sterile 305111 | Fisher Scientifique | 14-826-15 | For Laboratory Constructed Probes |
BD Needle 21 Gauge 1.5 Inch PrecisionGlide Sterile 305167 | Fisher Scientifique | 14-826-5B | For Laboratory Constructed Probes |
26G Stainless Steel Tubing One Foot | HRS Scientific | SST-26/FT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/20 .024" OD X .015" ID | HRS Scientific | C315CT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/10 .024" OD X .011" ID | HRS Scientific | C314CT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/50 .038" OD X .023" ID | HRS Scientific | C313CT | For Laboratory Constructed Probes |
30S WIRE ST.ST 0.008X 1’ Long | HRS Scientific | 008BSH/30S | For Laboratory Constructed Probes |
Polymicro Technologies Flexible Fused Silica Capillary Tubing Inner Diameter 50µm, Outer Diameter 150µm | Molex LLC Polymicro Technologies | 106815-0015 | For Laboratory Constructed Probes |
Spectra Por 132294 Micro-Dialysis Hollow Fiber Membranes 13 kD MWCO | Spectrum Labs | FSSP9778671 | For Laboratory Constructed Probes |
Stainless Steel Collar | Sirnay In.c | 304 | For Laboratory Constructed Probes / Custome made |
Name | Company | Catalog Number | Comments |
Concussion Apparatus | |||
Brass Weight | Rapido Métal Inc. | Attach metal loop to base | |
Metal Loop | Rona Inc. | Available at most hardware stores | |
PVC Guide Tube | Rona Inc. | Available at most hardware stores | |
Alluminum Foil | Alcan | Available at most grocery stores | |
Tape | Available commercially | ||
GSC Cast Iron Support Ring Stand | Fisher Scientifique | S13748 | |
U-Shaped Plexiglas Frame | Présentoirs PlexiPlus Inc. | Custom made | |
Foam Cushion | Mousse D&R Foam Inc. | Custom made | |
Razor Blades | VWR International | 55411-055 | |
Super Strong Trilene XT 20 lb. Berkley | Canadian Tire | Available at most hardware stores | |
Isoflurane | Baxter | CA2L9100 | |
Stop Watch | Available at most sporting goods retailer |
Animal Preparation | |||
Sprague Dawley Rats | Charles River Laboratories | SAS SD 40 | |
Name | Company | Catalog Number | Comments |
Microdialysis Guide Cannula Implantation Surgery | |||
Ketamine Hydrochloride (100 mg/ml) | Bioniche | 1989529 | |
Xylazine Hydrochloride (100 mg/ml) | Bimeda | 8XYL004C | |
Solution of Chlorhexidine Gluconate 2% and Isopropyl Alcohol 2% | Carefusion | 260100C | |
Lidocaine Hydrochloride | Alveda Pharma | 0122AG01 | |
Bupivacaine Hydrochloride | Hospira | 1559 | |
Ophthalmic Ointment | Baussh and Lomb inc. | 2125706 | |
Stereotaxic Frame | Stoelting | 51600 | |
Stereotaxic Cannula Holder Arm | Harvard Apparatus | 72-4837 | |
Drill | Dremel | 8050-N/18 | |
Suture Thread Coated Vicryl Rapide 4-0 | Ethicon | VR2297 | |
Dental Acrylic Cement | Harvard Apparatus | 72-6906 | |
Screws | JI Morris Company | P0090CE125 | |
Isoflurane | Baxter | CA2L9100 | |
Cannula Gauge 20 10.55mm | HRS Scientific | C311G/SPC | |
Dummy-Cannula 10.55mm | HRS Scientific | C311DC/1/SPC | |
Name | Company | Catalog Number | Comments |
Microdialysis Procedure | |||
CMA 402 Syringe Pump | Harvard Apparatus Canada | CMA-8003110 | |
Microsyringe 2.5ml Glass | Harvard Apparatus Canada | CMA-8309021 | |
Syringe Clip Medium For 1-2.5ml | Harvard Apparatus Canada | CMA-3408310 | |
Low-Torque Dual Channel Quartz-Lined Swivel | Instech Laboratories Inc. | 375/D/22QM | |
GSC Cast Iron Support Ring Stand | Fisher Scientifique | S13748 | |
Fisherbrand Castaloy Adjustable-Angle Clamps | Fisher Scientifique | 05769Q | |
NaHCO3 Sodium Bicarbonate | Sigma-Aldrich Canada | S5761-500G | For Artificial Cerebrospinal Fluid (aCSF) |
MgCl2 Magnesium Chloride | Sigma-Aldrich Canada | M8266-100G | For Artificial Cerebrospinal Fluid (aCSF) |
NaCl Sodium Chloride | Sigma-Aldrich Canada | S7653-1KG | For Artificial Cerebrospinal Fluid (aCSF) |
L-Ascorbic Acid | Sigma-Aldrich Canada | A5960-25G | For Artificial Cerebrospinal Fluid (aCSF) |
KCl Potassium Chloride | Sigma-Aldrich Canada | P9333-500G | For Artificial Cerebrospinal Fluid (aCSF) |
NaH2PO4 Sodium Phosphate Monobasic | Sigma-Aldrich Canada | S0751-1KG | For Artificial Cerebrospinal Fluid (aCSF) |
CaCl2 Calcium Chloride | Sigma-Aldrich Canada | 383147-100G | For Artificial Cerebrospinal Fluid (aCSF) |
Lighter | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Epoxy Glue | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Super Glue Gel | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Heat Shrink Tube 0.063" Inner Diameter Gardner Bender | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
Cut-Off Wheels Dremel #409 | Canadian Tire | For Laboratory Constructed Probes / Available at most hardware stores | |
BD Needle 26 Gauge 0.5 Inch PrecisionGlide Sterile 305111 | Fisher Scientifique | 14-826-15 | For Laboratory Constructed Probes |
BD Needle 21 Gauge 1.5 Inch PrecisionGlide Sterile 305167 | Fisher Scientifique | 14-826-5B | For Laboratory Constructed Probes |
26G Stainless Steel Tubing One Foot | HRS Scientific | SST-26/FT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/20 .024" OD X .015" ID | HRS Scientific | C315CT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/10 .024" OD X .011" ID | HRS Scientific | C314CT | For Laboratory Constructed Probes |
Polyethylene Tubing PE/50 .038" OD X .023" ID | HRS Scientific | C313CT | For Laboratory Constructed Probes |
30S WIRE ST.ST 0.008X 1’ Long | HRS Scientific | 008BSH/30S | For Laboratory Constructed Probes |
Polymicro Technologies Flexible Fused Silica Capillary Tubing Inner Diameter 50µm, Outer Diameter 150µm | Molex LLC Polymicro Technologies | 106815-0015 | For Laboratory Constructed Probes |
Spectra Por 132294 Micro-Dialysis Hollow Fiber Membranes 13 kD MWCO | Spectrum Labs | FSSP9778671 | For Laboratory Constructed Probes |
Stainless Steel Collar | Sirnay In.c | 304 | For Laboratory Constructed Probes / Custome made |
Name | Company | Catalog Number | Comments |
Concussion Apparatus | |||
Brass Weight | Rapido Métal Inc. | Attach metal loop to base | |
Metal Loop | Rona Inc. | Available at most hardware stores | |
PVC Guide Tube | Rona Inc. | Available at most hardware stores | |
Alluminum Foil | Alcan | Available at most grocery stores | |
Tape | Available commercially | ||
GSC Cast Iron Support Ring Stand | Fisher Scientifique | S13748 | |
U-Shaped Plexiglas Frame | Présentoirs PlexiPlus Inc. | Custom made | |
Foam Cushion | Mousse D&R Foam Inc. | Custom made | |
Razor Blades | VWR International | 55411-055 | |
Super Strong Trilene XT 20 lb. Berkley | Canadian Tire | Available at most hardware stores | |
Isoflurane | Baxter | CA2L9100 | |
Stop Watch | Available at most sporting goods retailer |