Role of endothelin receptor subtypes in the behavioral effects of the intracerebroventricular administration of endothelin-1 in conscious rats.
The role of endothelin receptor subtypes, i.e., ET(A) and ET(B) receptors, in the behavioral effects of the intracerebroventricular (ICV) administration of endothelin-1 were examined in conscious rats. ICV administration of endothelin-1 (1-9 pmol/rat) dose dependently produced barrel rolling and other convulsive behaviors including bodily twitching, rigidity, back crawling, fore/hindlimb dystonia, fore/hindlimb clonus, tail extension, and facial clonus. Moreover, a marked increase in spontaneous locomotor activity was observed in animals that were treated with a low dose of endothelin-1 (1 pmol/rat, ICV). Endothelin-1 (9 pmol/rat, ICV)-induced barrel rolling and other convulsive behaviors were completely suppressed by the coadministration of BQ-123 (15 nmol, ICV), a specific endothelin ET(A) receptor antagonist, but not of BQ-788 (15 nmol/rat, ICV), a specific endothelin ET(B) receptor antagonist. In contrast, increased locomotor activity produced by treatment with a low dose of endothelin-1 (1 pmol/rat, ICV) was antagonized by coadministration of BQ-788, but not of BQ123. These results indicate that endothelin-1, which has affinity for both endothelin ET(A) and ET(B) receptors, most likely acts on central ET(A) receptors to evoke barrel rolling and other convulsive behaviors. In addition, activation of central ET(B) receptors may be involved in the increase in spontaneous locomotor activity. These results suggest that brain endothelin receptor subtypes may be involved in the regulation of various physiological functions.
Nagasaka
J
J
Department of Pharmacology, Tokyo Medical University, Japan.
Tsuji
M
M
Takeda
H
H
Matsumiya
T
T
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007276:Injections, Intraventricular; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000187:drug effects*; D012640:Seizures / Q000139:chemically induced / Q000523:psychology
D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; C086539:BQ 788; C072247:cyclo(Trp-Asp-Pro-Val-Leu)