[Regulation of the postsynaptic alpha-1-adrenoreceptors of the smooth muscle of the nictitating membrane in the cat].

Radioassay binding of the smooth muscle of the nictitating membrane of cat has revealed the specific binding sites of [3H]prazosin corresponding to alpha-1 adrenoceptors. There was a significant increase in the number of alpha-1 adrenoceptors without any changes in their affinity. Incubation of the culture of the preliminary sympathectomized smooth muscle with noradrenaline decreased the number of alpha-1 adrenoceptors also without altering the affinity of binding. So, it is concluded that sympathetic nervous system regulated the number of postsynaptic alpha-1 adrenoceptors by means of neurotransmitter (noradrenaline).