DIETARY DOCOSAHEXAENOIC ACID INCREASES CEREBRAL ACETYLCHOLINE LEVELS AND IMPROVES PASSIVE-AVOIDANCE PERFORMANCE IN STROKE-PRONE SPONTANEOUSLY HYPERTENSIVE RATS

We have recently shown that inferior performance in passive avoidance task is accompanied with decreased hippocampal choline (Ch) in stroke- prone spontaneously hypertensive rats (SHRSP) compared with normotensi ve control Wistar-Kyoto rats (WKY). We also reported that dietary doco sahexaenoic acid (DHA) suppresses the development of hypertension and stroke-related behavioral changes, resulting in the prolongation of th e life span of SHRSP. In this study, we examined the effect of dietary DHA on the cerebral acetylcholine (ACh) levels and learning performan ce in passive avoidance tasks in SHRSP. The arachidonic acid decreased and the DHA increased in plasma lipids dose dependently with dietary DHA treatments, which decreased the systolic brood pressure in SHRSP. Dietary DHA significantly restored the significantly inferior learning performance in passive avoidance response observed in control SHRSP ( DHA 0%). Furthermore, the hippocampal ACh levels were correlated posit ively with the total response latency in passive avoidance tasks. Thes e results suggest that cholinergic dysfunction in the brain of control SHRSP is responsible, at least in part, for the impaired learning abi lity and the dietary DHA ameliorates this performance failure. (C) 199 7 Elsevier Science Inc.