Both α1B- and α1A-adrenoceptor subtypes are involved in contractions of rat spleen.
Pharmacol Rep
; 73(1): 255-260, 2021 Feb.
Article
em En
| MEDLINE
| ID: mdl-32860192
ABSTRACT
BACKGROUND:
The spleen is a reservoir for circulating blood cells, and can contract to expel them.METHODS:
We have investigated the adrenoceptors involved in isometric contractions of rat spleen produced by noradrenaline (NA) and the α1-adrenoceptor agonist phenylephrine (Phe).RESULTS:
Contractions to NA were antagonized by both the α1-adrenoceptor antagonist prazosin (10-8 M) and the α2-adrenoceptor antagonist yohimbine (10-6M), and the combination produced further shifts in NA potency. Contractions to Phe were antagonized by prazosin (10-8 M) which caused a marked parallel shift in the concentration-response curve. High non-selective concentrations of the α1D-adrenoceptor antagonist BMY7378 (10-6 M), the α1A-adrenoceptor antagonist RS100329 ((3 × 10-8 M), and the putative α1B-adrenoceptor antagonist cyclazosin (10-8 M) also produced parallel shifts in the Phe concentration-response curve. BMY7378 at the selective concentration of 3 × 10-8 M had no effect on responses to Phe, but RS100329 in the selective concentration of 3 × 10-9 M produced a marked shift in the effects of high concentrations of Phe. Hence, antagonists in concentrations that block both α1A- and α1B-adrenoceptors produce approximately parallel shifts in Phe potency.CONCLUSIONS:
Contractions of rat spleen to adrenergic agonists involve α2- and α1B-adrenoceptors, with a lesser role for α1A-adrenoceptors. This confirms the suggestion that smooth muscle contractions commonly involve multiple subtypes.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Baço
/
Receptores Adrenérgicos alfa 1
Limite:
Animals
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article