Muscarinic mobilization of choline in rat brain in vivo as shown by the cerebral arterio-venous difference of choline.

In anesthetized rats, the choline levels of cerebrospinal fluid and plasma obtained from blood collected from peripheral vessels (carotid artery, cardiac vessels) and from the transverse sinus were determined with a radioenzymatic assay. Cortical release of choline was studied using the "cup technique." The plasma choline level of the peripheral blood (11.5 mumol/L) was lower than that of the sinus blood. The resulting cerebral arterio-venous difference of choline was negative (3.2 mumol/L) and reflected the net release of choline from the whole brain. The plasma choline levels were not different irrespective of whether the rats were anesthetized with ether, urethane, or pentobarbital. Howe…