5-HT1A receptor-mediated inhibition of nucleus accumbens neurons activated by stimulation of parafascicular nucleus of thalamus.
Electrophysiological studies using chloral hydrate-anesthetized rats were performed to elucidate the role of serotonin1A (5-HT1A) receptors in the regulation of neuronal activity of nucleus accumbens (Acc) neurons receiving input from the parafascicular nucleus of the thalamus (Pf). Extracellular neuronal activities were recorded in Acc using a glass microelectrode attached along a seven-barreled micropipette, each barrel of which was filled with dopamine, 5-HT, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT: 5-HT1A agonist) hydrobromide, 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl]-piperazine (NAN-190: 5-HT1A antagonist) hydrobromide, glutamate and 2 M NaCl. These drugs were microiontophoretically applied to the immediate vicinity of the target neuron. Spikes elicited by Pf stimulation were inhibited by iontophoretically applied dopamine, 5-HT and 8-OH-DPAT in a dose-dependent manner. In these neurons, firing induced by iontophoretic application of glutamate was also suppressed by dopamine, 5-HT and 8-OH-DPAT. The 5-HT or 8-OH-DPAT-induced inhibitions of the glutamate-induced firing were antagonized by concomitant application of NAN-190. These findings suggest that the dopamine-sensitive Acc neurons receiving input from Pf are inhibited by 5-HT via 5-HT1A receptors located on postsynaptic Acc neurons.
Nagaoka
I
I
Department of Psychiatry and Neurosciences, Hiroshima University School of Medicine, Japan.
Sasa
M
M
Yamawaki
S
S
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D004298:Dopamine / Q000494:pharmacology; D004558:Electric Stimulation; D007478:Iontophoresis; D008297:Male; D009474:Neurons / Q000502:physiology*; D009714:Nucleus Accumbens / Q000166:cytology / Q000502:physiology*; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D013787:Thalamic Nuclei / Q000166:cytology / Q000502:physiology*
D010879:Piperazines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C058895:1-(2-methoxyphenyl)-4-(4-(2-phthalimido)butyl)piperazine; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D004298:Dopamine