A hypothesis linking intracellular sodium, membrane receptors, and hypertension

Studies in clinical and experimental hypertension have identified alterations both in intracellular [Na+] and in response to hormones and neurotransmitters. We propose a hypothesis that links these two alterations. Based on recent data showing that changes in intracellular [Na+] can alter the affinity and function of platelet alpha2-adrenergic receptors, we hypothesize that elevated intracellular [Na+] in hypertension leads to enhanced response at membrane receptors. This enhancement in response to hormones and/or neurotransmitters could then contribute to the development and maintenance of the hypertensive state. Because a variety of membrane receptors are Na+-sensitive (e.g., adrenergic, muscarinic cholinergic, opiate, angiotensin, dopamine, histamine H1), this mechanism may be operative at one or more receptor types located in tissues critical to the pathophysiology of hypertension.