INTRAHIPPOCAMPAL TRANSPLANTS OF SEPTAL CHOLINERGIC NEURONS - CHOLINE-ACETYLTRANSFERASE ACTIVITY, MUSCARINIC RECEPTOR-BINDING, AND SPATIAL MEMORY FUNCTION

Recent studies have demonstrated that intrahippocampal cholinergic sep tal grafts can ameliorate deficits in spatial memory function and hipp ocampal cholinergic neurochemical activity in animals with disruptions of the septohippocampal pathway. Further studies have revealed that h ippocampal cholinergic activity, as measured by high affinity choline uptake, correlates significantly with performance on tests of spatial memory function. The present study was designed to examine the effect of holinergic septal grafts on reversing deficits in hippocampal choli ne acetlytransferase activity and on normalizing muscarinic receptor b inding in animals with lesions of the septohippocampal system, and to examine the correlations between these cholinergic parameters and perf ormance of spatial memory tasks. The results of this study indicated t hat in animals with lesions plus septal grafts, hippocampal ChAT activ ity was restored significantly and muscarinic receptor binding was nor malized to a level not different from the control animals. Regression analyses indicated that ChAT activity was significantly correlated wit h performance on spatial reference memory, spatial navigation and spat ial working memory, while muscarinic receptor binding correlated signi ficantly with spatial reference memor performance.