Anthroylcholine bromide: a fluorescent ligand for the muscarinic receptor.
The action of anthroylcholine bromide, a new fluorescent probe, has been studied at the cellular (contraction of intestinal muscle) and subcellular levels (binding of 3H-quinuclidinyl benzilate to brain cortex membranes, fluorescence and enzyme activity) with the following results: 1. Anthroylcholine bromide competitively antagonized the contractile effect of acetylcholine in isolated rat duodenum (pA2 = 6.12), but had no effect either on the concentration response curves to histamine or to noradrenaline in isolated guinea pig ileum and rat vas deferens. 2. Anthroylcholine bromide displaced competitively 3H-quinuclidinyl benzilate from brain cortex membranes (Ki = 0.77 mumol/l). 3. Direct binding to the muscarinic site could be measured by exploiting the fluorescence properties of the probe. Binding displaceable by atropine (approximately 20% change in fluorescence) had an apparent affinity constant similar to that found with indirect methods. In contrast, d-tubocurarine did not displace the probe from its site, and atropine- or d-tubocurarine-sensitive binding of anthroylcholine bromide to Torpedo marmorata electric organ membranes, rich in nicotinic receptors, was not observed. These properties suggest the applicability of the probe to study the distribution, structure and/or kinetic properties of the muscarinic receptor.
Ripoll
C
C
Department of Physiology, University of Alicante, Spain.
Rubio
E
E
Soria
B
B
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D002794:Choline / Q000031:analogs & derivatives* / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D004386:Duodenum / Q000187:drug effects / Q000502:physiology; D004557:Electric Organ / Q000378:metabolism; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008024:Ligands; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D014101:Torpedo; D014403:Tubocurarine / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects / Q000502:physiology
D002800:Cholinesterase Inhibitors; D005456:Fluorescent Dyes; D008024:Ligands; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; C035321:9-anthroylcholine; D006632:Histamine; D002794:Choline; D000109:Acetylcholine; D014403:Tubocurarine; D009638:Norepinephrine