RT info:eu-repo/semantics/article
T1 Histamine H1-receptors modulate somatostatin receptors coupled to the inhibition of adenylyl cyclase in the rat frontoparietal cortex
A1 Puebla Jiménez, Lilian
A1 Ocaña Fuentes, Aurelio
A1 Arilla Ferreiro, Eduardo
K1 Mepyramine
K1 2-Pyridylethylamine
K1 Somatostatin receptor
K1 Adenylyl cyclase
K1 Rat
K1 Frontoparietal cortex
K1 Bioquímica
K1 Biochemistry
K1 Science
K1 Ciencia
AB Since exogenous histamine has been previously shown to increase the somatostatin (SS) receptor-effector system in the rat frontoparietal cortex and both histamine H1-receptor agonists and SS modulate higher nervous activity and have anticonvulsive properties, it was of interest to determine the participation of the H1-histaminergic system in this response. The intracerebroventricular (i.c.v.) administration of the specific histamine H1-receptor agonist 2-pyridylethylamine (PEA) (10 ¿g) to rats 2 h before decapitation increased the number of SS receptors (599 ± 40 vs 401 ± 31 femtomoles/mg protein, p< 0.01) and decreased their apparent affinity for SS (0.41 ± 0.03 vs 0.26 ± 0.02 nM, p < 0.01) in rat frontoparietal cortical membranes. No significant differences were seen for the basal and forskolin (FK)-stimulated adenylyl cyclase (AC) activities in the frontoparietal cortex of PEA-treated rats when compared to the control group. In the PEA group, however, the capacity of SS (10-4 M) to inhibit basal and FK (10-5 M)- stimulated AC activity in frontoparietal cortical membranes was significantly higher than in the control group (34 ± 1% vs 20 ± 2%, p < 0.001). The ability of low concentrations of the stable GTP analogue 5'- guanylylimidodiphosphate [Gpp(NH)p] to inhibit FK-stimulated AC activity in frontoparietal cortical membranes was similar in the PEA-treated and control animals. These results suggest that the increased SS-mediated inhibition of AC activity in the frontoparietal cortex of PEA-treated rats may be due to the increase of the number of SS receptors induced by PEA. Pretreatment with the H1-receptor antagonist mepyramine (30 mg/kg, intraperitoneally (IP) prevented the PEA-induced changes in SS binding and SS-mediated inhibition of AC activity. Mepyramine (30 mg/kg, IP) alone had no observable effect on the somatostatinergic system. The in vitro addition of PEA or mepyramine to frontoparietal cortical membranes obtained from untreated rats did not affect the SS binding parameters. Altogether, these results suggest that the H1- histaminergic system modulates the somatostatinergic system in the rat frontoparietal cortex.
PB Elsevier
SN 0196-9781
YR 1997
FD 1997
LK http://hdl.handle.net/10017/2315
UL http://hdl.handle.net/10017/2315
LA eng
NO Ministerio de Educación y Cultura
DS MINDS@UW
RD 20-abr-2024