[Locomotor activity and the nucleus accumbens]

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Locomotor activity is modulated by neurotransmitter systems in the brain.
• The nucleus accumbens plays a crucial role in regulating motor behavior.
• Apomorphine and picrotoxin are known to induce locomotor hyperactivity.

Purpose of the Study:

• To investigate the role of the nucleus accumbens in mediating drug-induced locomotor hyperactivity.
• To differentiate the mechanisms underlying apomorphine- and picrotoxin-induced hyperactivity.
• To examine the effects of local haloperidol and carbachol administration within the nucleus accumbens.

Main Methods:

• Locomotor hyperactivity was induced in rats using bilateral microinjections of apomorphine or picrotoxin into the nucleus accumbens.
• Behavior was assessed using an open field test.
• Systemic and intraaccumbens administration of drugs including haloperidol, carbachol, scopolamine, and methylatropine were employed.

Main Results:

• Systemic haloperidol abolished both apomorphine- and picrotoxin-induced hyperactivity.
• Intraaccumbens haloperidol and carbachol suppressed apomorphine-induced hyperactivity.
• Intraaccumbens administration of haloperidol and carbachol did not affect picrotoxin-induced hyperactivity.
• Intraaccumbens scopolamine and methylatropine had no effect on locomotor activity.

Conclusions:

• The nucleus accumbens is involved in mediating apomorphine-induced locomotor hyperactivity.
• The inhibitory effect of haloperidol on locomotor activity may involve mechanisms beyond dopamine antagonism within the nucleus accumbens.
• Apomorphine and picrotoxin likely act via distinct neurochemical pathways to induce hyperactivity.