Effects of chronic administration of carteolol on beta-adrenoceptors in spontaneously hypertensive rat heart.
We studied the effects of chronic administration of beta-adrenoceptor antagonists with and without intrinsic sympathomimetic activity (ISA): carteolol (with ISA) and propranolol (without ISA), respectively, on the heart of spontaneously hypertensive rat (SHR) and Wistar Kyoto rat (WKY). Six-week-old SHRs and WKYs were orally given carteolol or propranolol for ten weeks. The heart rate was reduced in propranolol-treated SHR, but not in carteolol-treated ones. In WKY, carteolol-treatment increased the heart rate. The number and affinities of beta-adrenoceptors were analyzed using [3H]dihydroalprenolol as a ligand. Propranolol at 30 mg/kg increased the number of cardiac beta-adrenoceptors in both SHR and WKY. In contrast, 10 mg/kg carteolol significantly decreased the number of cardiac beta-adrenoceptors in SHR, but not in WKY. These data indicate that carteolol, a beta-adrenoceptor antagonist with ISA, does not cause up-regulation of the number of cardiac beta-adrenoceptors in the rat and suggest that this fact is related to a possible lack of "rebound phenomena" after sudden discontinuation of chronic carteolol-therapy in humans.
Ebii
K
K
Department of Neurobiology, Kyoto Pharmaceutical University, Japan.
Fukunaga
R
R
Taniguchi
T
T
Fujiwara
M
M
Nakayama
S
S
Saitoh
Y
Y
Kimura
Y
Y
D000375:Aging; D000818:Animals; D001665:Binding Sites; D001794:Blood Pressure / Q000187:drug effects; D002354:Carteolol / Q000008:administration & dosage / Q000494:pharmacology*; D004082:Dihydroalprenolol / Q000378:metabolism; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011433:Propranolol / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism
D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D002354:Carteolol; D011433:Propranolol