Alpha1- and alpha2-adrenoceptors at different levels of the canine saphenous vein

• Type: Article in International Conference Proceedings Book
• Date: 1991

Authors

guimaraes, s (Author) Other; moura, d (Author) Other; nunes, jp (Author) FMUP; vaz-da-silva, mj (Author) FMUP; guimaraes, jt (Author) Other

Conference proceedings International

Title: Journal of Neural Transmission, Supplement

Pages: 163-169

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-007-5GD

Abstract (EN): Presynaptic alpha2- and postsynaptic alpha1-adrenoceptors were compared at the distal and proximal parts of the dog saphenous vein. The results obtained show that: (1) yohimbine is more effective against postsynaptic responses to phenylephrine distally than proximally. On the contrary, WB-4101 is more effective proximally; (2) phenylephrine increases inositol monophosphate production at both levels, but the increase is more pronounced distally; (3) UK-14,304 and adrenaline reduce and yohimbine and phentolamine increase the release of 3H-noradrenaline caused by electrical stimulation at both levels. However, while adrenaline as well as the antagonists are equipotent at the two levels, UK-14,304 is more potent distally than proximally. In conclusion, we suggest that: more alpha(1A)-adrenoceptors exist distally than proximally; imidazoline sites can exist at the distal level which contribute to the higher potency of UK-14,304 distally.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7