Excitatory effects of dopamine released by impulse flow in the rat nucleus accumbens in vivo

• Published in: Neuroscience 1996-11, Vol.75 (1), p.13-18
• Main Authors: Gonon, F., Sundstrom, L.
• Format: Article
• Language: English
• Subjects: Action Potentials - drug effects; Animals; Benzazepines - pharmacology; Biological and medical sciences; Central nervous system; Dopamine - physiology; Dopamine Antagonists - pharmacology; Electric Stimulation; Electrophysiology; Fundamental and applied biological sciences. Psychology; Haloperidol - pharmacology; Male; Microinjections; N-Methylaspartate - administration & dosage; N-Methylaspartate - pharmacology; Neurons - metabolism; Nucleus Accumbens - metabolism; Rats; Rats, Wistar; Receptors, Dopamine D1 - drug effects; Receptors, Dopamine D1 - physiology; Tegmentum Mesencephali - drug effects; Tegmentum Mesencephali - metabolism; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/0306-4522(96)00320-X

Dopamine is generally considered to be an inhibitory neurotransmitter in the central nervous system. Dopamine release in the nucleus accumbens can be evoked by chemical stimulation of the afferent cell bodies using N-methyl-D-aspartate microinjection in the ventral tegmental area. We report here that following such injections most neurons of the nucleus accumbens were excited. This excitation was abolished if dopaminergic neurons were lesioned and was blocked by antagonists of the D1 dopamine receptors. Finally, excitatory responses to electrical stimulation of the hippocampus were strongly facilitated by endogenously released dopamine. We suggest, therefore, that under physiological conditions, dopamine acting on D1 receptors is actually an excitatory neurotransmitter.