In vivo effects of local activation and blockade of 5-HT1B receptors on globus pallidus neuronal spiking

• Published in: Brain research 2005-05, Vol.1043 (1), p.186-194
• Main Authors: Querejeta, Enrique, Oviedo-Chávez, Aldo, Araujo-Alvarez, Juan Manuel, Quiñones-Cárdenas, Alma Rosa, Delgado, Alfonso
• Format: Article
• Language: English
• Subjects: 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; Action Potentials - drug effects; Action Potentials - physiology; Anesthesia; Animals; Basal ganglia; Behavior, Animal - drug effects; Biological and medical sciences; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Denervation; Fluoxetine; Fluoxetine - pharmacology; Fundamental and applied biological sciences. Psychology; Globus Pallidus - cytology; Globus Pallidus - drug effects; Globus Pallidus - physiology; L-694,247; Male; Medical sciences; Methiothepin; Methiothepin - pharmacology; Neurons - drug effects; Neurons - physiology; Neuropharmacology; Oxadiazoles - pharmacology; Pharmacology. Drug treatments; Piperazines - pharmacology; Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease); Psychology. Psychoanalysis. Psychiatry; Psychopharmacology; Pyridines - pharmacology; Quinolinic Acid; Rats; Rats, Wistar; Receptor, Serotonin, 5-HT1B - metabolism; Serotonergic pathways; Serotonin; Serotonin - pharmacology; Serotonin 5-HT1 Receptor Antagonists; Serotonin Antagonists - pharmacology; Serotonin Receptor Agonists - pharmacology; Serotonin Uptake Inhibitors - pharmacology; Tryptamines - pharmacology; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2005.02.055

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.