Monitoring Dopamine Release in a Rat Model with VTA Dopaminergic Neuron Receptor Manipulation

Abstract

Source: Wickham, R. J., et al. Combined Infusion and Stimulation with Fast-Scan Cyclic Voltammetry (CIS-FSCV) to Assess Ventral Tegmental Area Receptor Regulation of Phasic Dopamine. J. Vis. Exp. (2020).

This video demonstrates the implantation of electrodes and cannulas in an anesthetized rat to measure dopamine release in the nucleus accumbens using a potentiostat and the infusion of drugs to modulate dopaminergic activity in the ventral tegmental area.

Protocol

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Presurgical preparations

1. Electrode solution preparation
   1. To make the electrode backfill solution, prepare a solution of 4 M potassium acetate with 140 mM potassium chloride.
2. Electrode preparation
   1. Using vacuum suction, insert a T-650 carbon fiber (7 µm in diameter) into a borosilicate glass capillary (length = 100 mm, diameter = 1.0 mm, inside diameter = 0.5 mm).
   2. Once the carbon fiber has been placed insid....

Results

Figure 1: Timeline for recording before and after VTA microinfusion.

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Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Electrode Filling Solution/Supplies
Micropipette	World Precision Instruments	MF286-5 (28 gauge)
Potassium Acetate	Sigma	236497-100G
Potassium Chloride	Sigma	P3911-25G
Electrode Supplies
Carbon fiber	Thornel	T650
Electrode puller	Narishige International	PE-22	Note: horizontal pullers can be used as well
Glass capillary	A-M systems	626000
Insulated wires for electrodes	Weico Wire and Cable Incorporated	UL 1423	Length; 10 cm; diameter,0.4mm; must get custom made; insulated material should cover 5 cm of the wire
Light Microscope (for viewing and cutting electrode)	Fischer Scientific	M3700
Pin	Phoenix Enterprises	HWS1646	To be soldered onto the insuled electrode wire and reference electrode; connects to headstage
Putty	Alcolin	23922-1003	Used to place electrode on while cutting the carbon fiber
Scalpal Blade	World Precision Instruments	500239	For cutting carbon fiber to the apprpriate length
Silver Wire	Sigma	327026-4G
FSCV Hardware/Software
Faraday Cage	U-Line	H-3618 (36" x 24" x 42")
Potentiostat	Univ. of N. Carolina, Electronics Facility
Stimulating electrode	PlasticsOne	MS303/2-A/SPC	when ordering, request a 22 mm cut below pedestal
TarHeel HDCV Software	University of North Carolina-Chapel Hill	-	https://chem.unc.edu/critcl-main/criticl-electronics/criticl-electronics-hardware/ for ordering information
UEI breakout box	Univ. of N. Carolina, Electronics Facility		https://chem.unc.edu/critcl-main/criticl-electronics/criticl-electronics-hardware/ for ordering information
UEI power supply	Univ. of N. Carolina, Electronics Facility		https://chem.unc.edu/critcl-main/criticl-electronics/criticl-electronics-hardware/ for ordering information
Stimulator Hardware
Neurolog stimulus isolator	Digitimer Ltd.	DS4	Neurolog 800A
Infusion/Stimulation Supplies
Infusion Pump	New Era Syringe Pump	NE-300
Internal Cannula	PlasticsOne	C315I/SPC INTERNAL 33GA
Microliter Syringe	Hamilton	80308
Tubing	PlasticsOne	C313CT/ PKG TUBING 023 X 050 PE50
Surgical Supplies
Cannula Holder	Kopf Instruments	1776 P-1
Cotton Tip Applicators	Vitality Medical	806
Electrode Holder	Kopf Instruments	1770
Heating Pad	Kent Scientific	RT-0501
Povidone Iodine	Vitality Medical	29906-004
Screws	Stoelting	Bone Anchor Screws/Pkg.of 100	1.59 mm O.D., 3.2 mm long
Silver wire reference with AgCl	InVivo Metric	E255A
Square Gauze	Vitality Medical	441408
Stereotax	Kopf Instruments	Model 902 (Dual Arm Bar)
Drugs for infusions
((2R)-amino-5-phosphonovaleric acid	Sigma Aldrich	A5282
N-methyl-D-aspartate	Sigma Aldrich	M3262
Mecamylamine hydrochloride (M9020-5mg)	Sigma Aldrich	M9020
Scopolamine hydrobromide (S0929-1g)	Sigma Aldrich	S0929