Operant Self-Administration with Microdialysis
Objective: Test the hypothesis that naltrexone attenuates ethanol's rewarding properties by interfering with ethanol-induced dopamine stimulation in the nucleus accumbens, using simultaneous operant self-administration and intracranial microdialysis measurements
Gather these items before starting the experiment. Check off items as you prepare.
Equipment2
Materials3
Software1
Not specified • Not mentioned
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Protocol Steps
Training phase - Ethanol self-administration
Male Wistar rats trained to self-administer ethanol solution
Note: Training continued until reliable self-administration was established before surgical preparation
View evidence from paper
“Male Wistar rats were trained to self-administer ethanol (10–15%, w/v) in 0.2% (w/v) saccharin during daily 30 min sessions”
Surgical preparation
Rats surgically prepared for intracranial microdialysis
Note: Performed after training but before experimental testing
View evidence from paper
“were surgically prepared for intracranial microdialysis. Experiments began after reliable self-administration was established”
Drug injection
Rats injected with either naltrexone or saline control
Note: Subcutaneous injection; 10 minutes before chamber placement
View evidence from paper
“Rats were injected with naltrexone (0.25 mg/kg, s.c.) or saline and 10 min later were placed inside the operant chamber”
Waiting period
Rats placed in operant chamber with no ethanol available
Note: Follows 10 minute post-injection interval; microdialysis measurements ongoing
View evidence from paper
“10 min later were placed inside the operant chamber for a 20 min waiting period with no ethanol available”
Ethanol access period
Rats given access to ethanol solution for operant self-administration
Note: Follows waiting period; simultaneous microdialysis measurement of dopamine levels
View evidence from paper
“followed by 30 min of access to ethanol”
Dopamine measurement
Continuous measurement of dialysate dopamine levels in nucleus accumbens throughout waiting and ethanol access periods
Note: Simultaneous with behavioral measurements of operant responding
View evidence from paper
“Simultaneous measures of the effects of naltrexone on dialysate dopamine levels in the NAcc and on operant responding for oral ethanol”