Effects of d-tubocurarine on the submandibular salivary gland

¹ Department of Physiology, University of Michigan, Ann Arbor, Michigan

First injections of d-tubocurarine in doses of 0.3–1.5 mg (2–10 u) into the arterial blood supply, limited to acutely denervated submandibular salivary glands of anesthetized dogs, resulted in a prompt and large transient increase in the blood flow through the gland and, when the dose was sufficient, initiation of a transient secretion of saliva. Both the vascular and secretory responses diminished progressively with repeated administrations of the drug. Preadministration of diphen-hydramine (Benadryl) reduced the vascular and secretory responses to ‘first’ injections of d-tubocurarine, suggesting that histamine released from the glandular tissue might be an intermediary for the observed effects. Increased levels of histamine in the effluent blood plasma after administration of d-tubocurarine, as determined by biological assay, supported this role for histamine. Systemic administration of d-tubocurarine, with the gland normally innervated, but vascularly isolated and perfused, yielded no evidence for a possible centrally initiated vasodilatation and salivation.