Cholinergic neurons in numerous brain regions have been implicated in blood pressure regulation. One of the most important brain regions where cholinergic neurons play a role in the pathogenesis of
hypertension is the rostral ventrolateral medulla (RVL), an essential source of efferent sympathetic activity. Pharmacological and biochemical studies have revealed that
acetylcholine release in the RVL is increased in experimental
hypertension regardless of its etiology and that this enhanced release of
acetylcholine leads to
hypertension. The lateral parabrachial nucleus, another important hindbrain area involved in blood pressure regulation, is responsible for the enhanced release of
acetylcholine in the RVL of hypertensive animals. Moreover, recent studies have demonstrated the involvement of the hypothalamic defence area, an area believed to be involved in the
hypertension induced by chronic stress, in the release of
acetylcholine in the RVL and also have demonstrated the existence of direct projections from the hypothalamic structures to the lateral parabrachial nucleus. More studies about mechanisms of the enhanced release of
acetylcholine in the RVL of experimentally hypertensive animals will provide important information for central mechanisms of
hypertension.