Intact human lymphocyte membranes respond to muscarinic receptor stimulation by oxotremorine with marked changes in microviscosity and an increase in cyclic GMP.
The muscarinic agonist oxotremorine produced a linear dose-dependent increase in membrane fluidity of intact and viable human lymphocytes in vitro. This effect proved to be receptor-mediated because preincubation with 10(-5)M atropine shifted the dose-response curve one order of magnitude rightward. Pirenzepine preincubation did not affect membrane fluidity variation. A cGMP increase was also found after oxotremorine treatment. The results are discussed in terms of possible modulation of guanyl cyclase and adenyl cyclase through membrane fluidity variations.
D001285:Atropine / Q000494:pharmacology; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006152:Cyclic GMP / Q000097:blood*; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D010095:Oxotremorine / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D014783:Viscosity
D011976:Receptors, Muscarinic; D010095:Oxotremorine; D001285:Atropine; D006152:Cyclic GMP