The mechanism of action of mercuric chloride on the isolated perfused rat kidney.

Studies on 80 rat kidneys, perfused at constant flow, showed that mercuric chloride produced a marked increase in perfusion pressure within five minutes of administration. Adrenergic blocking agents (phentolamine and propranolol), angiotensin sensitivity depletion, bradykinin and low concentrations of mannitol had no effect on this increase in resistance. Perfusion of the kidney with 5 percent mannitol solution, however, significantly reduced the increase of vascular resistance induced by mercuric chloride. Evidence is presented that mercuric chloride may evoke an increase in vascular resistance by inducing endothelial cell swelling, an action antagonised by the hypertonic effect of mannitol. Other possible contributory mechanisms are also discussed.