M3-muscarinic receptor mediates prejunctional inhibition of noradrenaline release and the relaxation in cat femoral artery

J Pharm Pharmacol. 1991 Sep;43(9):644-9. doi: 10.1111/j.2042-7158.1991.tb03555.x.

Abstract

The aim of the present study was to analyse the muscarinic receptors involved in the vasodilation elicited by acetylcholine (ACh) and the carbachol inhibition of electrically-evoked [3H]noradrenaline (NA) release in cat femoral artery. For this purpose, the following receptor antagonists were used, atropine, pirenzepine (M1-antagonist), AF-DX 116 (M2-antagonist) and 4-diphenylacetoxy-N-methylpiperidine methobromide (4-DAMP; M3-antagonist). The order of potency (pA2 values) of these drugs at postjunctional level was: atropine (9.7) greater than or equal to 4-DAMP (9.6) greater than pirenzepine (7.2) greater than AF-DX 116 (6.0), and at prejunctional level (pIC50 values) was: 4-DAMP (9.3) greater than atropine (8.5) greater than AF-DX 116 (7.1) greater than pirenzepine (5.9). These findings indicate that the muscarinic receptors mediating the vasodilation induced by ACh and the carbachol inhibition of NA release are of the M3-subtype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / antagonists & inhibitors
  • Acetylcholine / pharmacology
  • Animals
  • Carbachol / antagonists & inhibitors
  • Carbachol / pharmacology
  • Cats
  • Electric Stimulation
  • Endothelium, Vascular / drug effects*
  • Female
  • Male
  • Muscle, Smooth, Vascular / drug effects*
  • Muscle, Smooth, Vascular / metabolism
  • Neuroeffector Junction / drug effects
  • Norepinephrine / metabolism*
  • Parasympatholytics / pharmacology*
  • Receptors, Muscarinic / drug effects*

Substances

  • Parasympatholytics
  • Receptors, Muscarinic
  • Carbachol
  • Acetylcholine
  • Norepinephrine