The binding of L-[3H]nicotine to a single class of high affinity sites in rat brain membranes.

摘要: The binding of optically pure L-[3H]nicotine to rat brain membrane preparations was studied using a rapid filtration method. properties observed depended on the method used for tissue isolation. most consistent results were obtained with membranes prepared in presence protease inhibitors, without divalent cations. Binding saturable, reversible, and stereospecific. Scatchard analysis revealed single class high affinity sites an average KD 2 nM Bmax approximately 200 fmol/mg protein. Hill coefficient near unity. calculated from kinetic rate constants association (k1 = 0.012 min-1 nM-1) dissociation (k-1 0.04 min-1) around 3 nM, good agreement constant determined equilibrium binding. In competition studies, cholinergic agonists generally effective inhibiting binding, whereas antagonists relatively ineffective. D-isomer nicotine about 60-fold less potent than L-isomer unaffected by temperature, exception that somewhat lower at 37 degrees. these essentially identical adult male female brain. However, fetal tissue. present findings are idea there is nicotinic cholinoceptive properties.