Sensitization to and conditioning with apomorphine in pigeons

Area of Science:

• Behavioral pharmacology
• Neuroscience
• Animal behavior

Background:

• Drug sensitization is a phenomenon where repeated drug administration leads to increased behavioral responses.
• Environmental cues are known to influence drug effects through classical conditioning.
• Apomorphine is a dopamine receptor agonist with known behavioral effects in various species.

Purpose of the Study:

• To investigate the role of environmental cues in the development of behavioral sensitization to apomorphine in pigeons.
• To determine if apomorphine exhibits reinforcing properties in pigeons, as suggested by place preference conditioning.

Main Methods:

• Pigeons were administered apomorphine or saline in distinct environments.
• Behavioral responses to apomorphine were measured after repeated drug exposure.
• A place preference paradigm was used to assess the reinforcing properties of apomorphine.

Main Results:

• Pigeons repeatedly exposed to apomorphine in the same environment showed significantly augmented behavioral responses compared to controls.
• Environmental cues associated with apomorphine administration became conditioned stimuli, eliciting drug-like responses.
• Pigeons developed a preference for environments where they had previously received apomorphine, indicating reinforcing effects.

Conclusions:

• Behavioral sensitization to apomorphine in pigeons is significantly influenced by environmental conditioning.
• Apomorphine possesses reinforcing properties in birds, similar to its effects in mammals.
• Environmental context is a critical factor in understanding and potentially modulating drug-induced behavioral changes.