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The effects of phencyclidine, ketamine, delta-amphetamine and pentobarbital on schedule-controlled behavior in the
Abstract:
The response of mice of breaking a light beam onto a photocell was programmed to produce food according to a multiple schedule with alternating 30-response fixed ratio, 300-second fixed interval (FR-30 FI-300 sec) components. Training was standardized for all mice, and stable patterns of responding that were similar to those described for other species and responses under this schedule developed quickly. The effects of pentobaribtal, delta-amphetamine, phencyclidine and ketamine were studied. At some dose, each of the four drugs produced an increase in rate of responding; the increase was proportionately greater at low rates of responding than at higher rates. At some dose range, delta-amphetamine, ketamine and phencyclidine produced dose-related increases in FI average rates were to 1.83, 1.25 and 1.32 times the control rate for delta-amphetamine (1 mg/kg), ketamine (100 mg/kg) and phencyclidine (3 mg/kg), respectively. Phencyclidine and ketamine thus showed some "amphetamine-like" effects in the mouse. Pentobarbital increased (1.25 times the control rate) both the FR and FI response rates at a dose of 3 mg/kg. Higher doses of pentobarbital progressively decreased both FR and FI response rates in a parallel fashion.
Insights
This study investigated how four drugs affect mouse behavior under a complex food reward schedule. Delta-amphetamine, phencyclidine, and ketamine increased response rates, showing amphetamine-like effects, while pentobarbital had dose-dependent effects.
Area of Science:
- Behavioral pharmacology
- Neuroscience
- Animal behavior
Background:
- Mice were trained to respond to a light beam for food rewards using a multiple schedule.
- This schedule involved alternating fixed ratio (FR-30) and fixed interval (FI-300 sec) components.
- Stable responding patterns emerged quickly, comparable to other species.
Purpose of the Study:
- To examine the effects of pentobarbital, delta-amphetamine, phencyclidine, and ketamine on mouse behavior.
- To determine dose-response relationships for these drugs under the established schedule.
- To identify any amphetamine-like effects of phencyclidine and ketamine.
Main Methods:
- Mice were subjected to a multiple FR-30 FI-300 sec schedule of reinforcement.
- The effects of four drugs (pentobarbital, delta-amphetamine, phencyclidine, ketamine) were administered at various doses.
- Response rates for both FR and FI components were measured and compared to control conditions.
Main Results:
- All four drugs increased response rates at certain doses, with greater proportional increases at lower rates.
- Delta-amphetamine, ketamine, and phencyclidine demonstrated dose-related increases in fixed interval response rates.
- Phencyclidine and ketamine exhibited amphetamine-like behavioral effects in mice.
Conclusions:
- Pentobarbital, delta-amphetamine, phencyclidine, and ketamine modulate operant responding in mice.
- Phencyclidine and ketamine share some behavioral characteristics with delta-amphetamine.
- Pentobarbital's effects are dose-dependent, increasing rates at low doses and decreasing them at higher doses.