title: Use of 3H-QNB in the isolation of plasma membrane from smooth muscle of the urinary bladder: effect of oxalate on calcium uptake by the membrane fractions.
abstract: Specific binding of tritiated quinuclidinyl benzilate (3H-QNB) to surface membrane muscarinic receptors was utilized to identify plasma membrane (PM) fractions from smooth muscle of the rabbit urinary bladder. Accumulation of 3H-QNB in the PM fraction was 4-5-fold higher than that in fractions of endoplasmic reticulum (EM) or mitochondria (M). A similar pattern of distribution was found for 5'-nucleotidase. 3H-QNB binding therefore appears to be a suitable marker for plasma membrane of the urinary bladder. Data on ATP-dependent calcium uptake by PM and ER fractions showed that oxalate highly potentiated calcium uptake by both fractions and consequently this feature cannot be used to identify ER fractions specifically.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D008928:Mitochondria / Q000378:metabolism; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010070:Oxalates / Q000494:pharmacology*; D019815:Oxalic Acid; D011812:Quinuclidines / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D011817:Rabbits; D011976:Receptors, Muscarinic / Q000378:metabolism; D014316:Tritium; D001743:Urinary Bladder / Q000187:drug effects / Q000378:metabolism
chemical_list: D010070:Oxalates; D011812:Quinuclidines; D011976:Receptors, Muscarinic; D014316:Tritium; D011813:Quinuclidinyl Benzilate; D001285:Atropine; D019815:Oxalic Acid; D002118:Calcium