Identification of muscarinic receptors in rat cerebral cortical microvessels.
Microvessels isolated from rat cerebral cortex consist mainly of capillaries (greater than 85%). Fresh, intact microvessel preparations have been analyzed by radioligand binding techniques for muscarinic receptors. Scatchard analysis of specific quinuclidinyl benzilate (QNB) binding indicates that microvessels possess a large number of muscarinic sites (914 fmol/mg protein) of high affinity (KD = 0.034 nM). The association and dissociation rate constants (0.37 min-1 nM-1 and 0.0067 min-1, respectively) yield an equilibrium KD of 0.018 nM. Displacement of [3H]QNB by muscarinic ligands and control substances is typical of muscarinic receptors. The results indicate that cerebral microvessels possess a large population of muscarinic receptors.
D000818:Animals; D002196:Capillaries / Q000032:analysis*; D002540:Cerebral Cortex / Q000098:blood supply*; D007700:Kinetics; D008297:Male; D008833:Microcirculation; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011950:Receptors, Cholinergic / Q000032:analysis*; D011976:Receptors, Muscarinic / Q000032:analysis* / Q000378:metabolism
D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate