POSTSYNAPTIC ALPHA-ADRENOCEPTOR SUBTYPES IN THE INTERNAL CAROTID, MESENTERIC, SPLENIC, RENAL AND FEMORAL VASCULAR BEDS OF THE DOG

• Type: Article in International Scientific Journal
• Date: 1986

Authors

POLONIA, JJ (Author) FMUP; GUERREIRO, M (Author) Other; GUIMARAES, S (Author) Other; GARRETT, J (Author) Other

Journal

Title: Archives Internationales de Pharmacodynamie et de Therapie

Vol. 279

Pages: 5-16

ISSN: 0003-9780

Publisher: Blackwell

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 7 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-001-W0A

Abstract (EN): Pressor effects of noradrenaline, phenylephrine and ¿-methylnoradrenaline and the inhibition of these effects by prazosin or yohimbine (or both) were studied in vivo in the renal, splenic, femoral, anterior mesenteric and internal carotid vascular beds of the dog. In all the vascular beds noradrenaline was more potent than ¿-methylnoradrenaline and ¿-methylnoradrenaline was more potent than phenylephrine. However, the ratios between the ED50 for phenylephrine and the ED50 for ¿-methylnoradrenaline in the mesenteric, in the femoral, in the splenic and in the renal circulations was 2.19, 1.89, 1.48, and 1.33, respectively, showing that the relative potency of phenylephrine increased in that order. In the internal carotid vascular bed it was not possible to determine any value. Furthermore, in the renal vascular bed, prazosin (100 ¿g/kg) inhibited pressor responses to all agonists more readily than yohimbine (250 ¿g/kg) and yohimbine was more potent than prazosin against all the agonists in the mesenteric and in the femoral vascular beds. Our results show that: 1) there are both postsynaptic ¿1- and ¿2-adrenoceptors in the four vascular beds; 2) the contribution of ¿2-adrenoceptors to pressor responses to sympathomimetic agents is maximal in the mesenteric followed by the femoral, the splenic and the renal vascular bed, whereas the participation of ¿1-adrenoceptors is maximal in the renal and progressively smaller in the splenic, in the femoral and in the mesenteric vascular bed, where it reaches the lowest value.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12