hemicholinium3 binding correlation with highaffinity choline uptake during changes in cholinergic activity the binding of hemicholinium3 was measured in the cerebral cortex hippocampus and striatum after treatment with cholinergic agonists and antagonists in order to examine its utility as an index of presynaptic cholinergic regulation the binding of muscarinic receptors and the high affinity uptake of choline were examined in the same tissue subacute treatment with physostigmine or arecoline decreased all three parameters while they were increased by treatment with atropine the binding of hemicholinium3 correlated significantly with the high affinity uptake of choline it may therefore be a useful reflection of this phase of cholinergic regulation under conditions where measurement of the uptake of choline is not feasible including autoradiographic and post mortem studies