In vivo effects of local activation and blockade of 5-HT1B receptors on globus pallidus neuronal spiking.
Several morphological works have shown that the globus pallidus (GP) contains the highest density of 5-HT1B receptors within the telencephalon. However, the role of these receptors in the spiking of GP neurons in vivo is unknown. In the present work, we use single-unit extracellular recordings in the anesthetized rat to analyze changes in the firing rate of GP neurons evoked by local activation and blockade of 5-HT1B receptors. Intrapallidal administration of serotonin, or the serotonin uptake inhibitor fluoxetine, predominantly produced an excitatory effect in the basal firing rate of GP neurons. The 5-HT1B receptor agonist, L-694,247, caused a dose-dependent excitatory effect on most pallidal neurons tested. Blockade of 5-HT1B receptors by intrapallidal application of methiothepin predominantly caused inhibition in GP neurons firing rate. Moreover, methiothepin diminished the excitatory effect evoked by L-694,247. Furthermore, local serotonin did not evoke significant changes in the basal firing rate of GP neurons in unilateral striatal lesioned rats. Taken all together, these results suggest that serotonin 5-HT1B receptors significantly contribute to the control of spiking of the rat GP neurons, and that the 5-HT1B receptors exerting this control are most likely localized in the striato-pallidal pathway.
Querejeta
Enrique
E
Sección de Estudios de Posgrado e Investigación Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Diáz Mirón, Casco de Santo Tomás, C.P. 11340, México D.F., Mexico. equerejeta@ipn.mx
Oviedo-Chávez
Aldo
A
Araujo-Alvarez
Juan Manuel
JM
Quiñones-Cárdenas
Alma Rosa
AR
Delgado
Alfonso
A
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000758:Anesthesia; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003714:Denervation; D005473:Fluoxetine / Q000494:pharmacology; D005917:Globus Pallidus / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D008719:Methiothepin / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010069:Oxadiazoles / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D017378:Quinolinic Acid; D051381:Rats; D017208:Rats, Wistar; D044302:Receptor, Serotonin, 5-HT1B / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology; D058829:Serotonin 5-HT1 Receptor Antagonists; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology; D014363:Tryptamines / Q000494:pharmacology*
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D005473:Fluoxetine; D008719:Methiothepin; D010069:Oxadiazoles; D010879:Piperazines; D011725:Pyridines; D017378:Quinolinic Acid; D044302:Receptor, Serotonin, 5-HT1B; D012701:Serotonin; D058829:Serotonin 5-HT1 Receptor Antagonists; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors; D014363:Tryptamines; C085632:L 694247; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide