Nitric oxide synthesis inhibition does not affect brain stimulation reward

Area of Science:

• Neuroscience
• Pharmacology

Background:

• Nitric oxide (NO) is implicated in neurotransmission and neuromodulation.
• Its role in reward pathways, particularly dopamine-dependent ones, remains unclear.

Purpose of the Study:

• To investigate the role of nitric oxide synthesis in brain stimulation reward.
• To determine if nitric oxide modulates cocaine's effects on reward pathways.

Main Methods:

• Administered N omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, at various doses.
• Assessed effects on frequency thresholds for brain stimulation reward.
• Examined L-NAME's impact on cocaine's facilitation of brain stimulation reward.

Main Results:

• L-NAME did not alter frequency thresholds for brain stimulation reward.
• Nitric oxide synthesis inhibition did not affect cocaine's ability to lower reward thresholds.
• L-NAME did not attenuate cocaine's effects, even at doses that reduce cerebral blood flow.

Conclusions:

• Nitric oxide is not involved in the dopamine-dependent rewarding effects of electrical brain stimulation.
• Nitric oxide does not mediate the reward facilitation caused by cocaine.
• Findings argue against pharmacokinetic explanations for L-NAME's effects on cocaine-induced behaviors.