TY - JOUR
T1 - In vivo effects of local activation and blockade of 5-HT1B receptors on globus pallidus neuronal spiking
AU - Querejeta, Enrique
AU - Oviedo-Chávez, Aldo
AU - Araujo-Alvarez, Juan Manuel
AU - Quiñones-Cárdenas, Alma Rosa
AU - Delgado, Alfonso
N1 - Funding Information:
The authors are grateful to Dr. Adriana Galvan and Dr. Rosa A. Bobadilla for their critical comments on the manuscript. The authors would like to thank Psicofarma S.A. de C.V. for the generous gift of fluoxetine. This study was supported by grant No. I-35643-B from CONACyT and funding from CGEPI-IPN.
PY - 2005/5/10
Y1 - 2005/5/10
N2 - 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.
AB - 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.
KW - Basal ganglia
KW - Fluoxetine
KW - L-694,247
KW - Methiothepin
KW - Serotonergic pathways
KW - Serotonin
UR - http://www.scopus.com/inward/record.url?scp=18044364022&partnerID=8YFLogxK
U2 - 10.1016/j.brainres.2005.02.055
DO - 10.1016/j.brainres.2005.02.055
M3 - Artículo
C2 - 15862532
SN - 0006-8993
VL - 1043
SP - 186
EP - 194
JO - Brain Research
JF - Brain Research
IS - 1-2
ER -