Chronic delta 9-tetrahydrocannabinol administration and schedule-induced aggression

Area of Science:

• Behavioral pharmacology
• Cannabinoid research
• Animal models in neuroscience

Background:

• Delta 9-tetrahydrocannabinol (delta 9-THC) is a primary psychoactive component of cannabis.
• Understanding the behavioral effects of delta 9-THC is crucial for its therapeutic and recreational applications.
• Pigeons are established models for studying operant behavior and drug effects.

Purpose of the Study:

• To investigate the impact of delta 9-THC on operant behavior (key-pecking) and schedule-induced aggression in pigeons.
• To assess the development of tolerance to the behavioral effects of repeated delta 9-THC administration.
• To differentiate the effects of delta 9-THC on different behavioral measures.

Main Methods:

• Pigeons were trained on a response-initiated fixed interval (FI) schedule for food.
• Pigeons were administered acute doses of delta 9-THC (0.5 mg/kg and 1.0 mg/kg).
• Key-pecking rates and schedule-induced aggression (attack responding) were measured before and after drug administration.

Main Results:

• Both key-pecking and attack responding were significantly reduced immediately after delta 9-THC administration.
• Pigeons developed tolerance to the rate-decreasing effects of delta 9-THC on key-pecking over repeated sessions.
• The suppressant effect of delta 9-THC on attack responding persisted with minimal recovery throughout the study.

Conclusions:

• Delta 9-THC exerts dose-dependent effects on operant behavior and aggression in pigeons.
• Tolerance develops to the disruptive effects of delta 9-THC on key-pecking but not on schedule-induced aggression.
• These findings suggest differential mechanisms underlying the effects of delta 9-THC on distinct behavioral outputs.