Sphingosine inhibits muscarinic cholinergic receptor binding in rat parotid acinar cells.
1. Sphingosine inhibited the binding of [3H]quinuclidinyl benzilate (QNB), a potent and specific muscarinic antagonist, in dispersed rat parotid acinar cells. 2. The inhibition of [3H]QNB binding was expressed as decrease in affinity without significant change of a number of membrane sites. 3. The effect of sphingosine on the binding was not affected by the chelation of extracellular Ca2+. 4. H-7, an inhibitor of protein kinase C, failed to decrease [3H]QNB binding. 5. Stearylamine, an analogue of sphingosine, was as effective as sphingosine in inhibiting [3H]QNB binding. 6. These results suggest that sphingosine inhibits muscarinic cholinergic receptor binding by a mechanism that is independent on extracellular Ca2+ and protein kinase C.
Department of Physiology, Nihon University School of Dentistry, Chiba, Japan.
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Fujita
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Sugiya
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000588:Amines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D010306:Parotid Gland / Q000187:drug effects / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D013110:Sphingosine / Q000494:pharmacology*
D000588:Amines; D007546:Isoquinolines; D010879:Piperazines; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; C009317:stearylamine; D013110:Sphingosine; D002118:Calcium