AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 1 102-R112, Copyright © 1980 by American Physiological Society
Regulation of body volume by salivation in a tick challenged with fluid loads
W. R. Kaufman, A. A. Aeschlimann and P. A. Diehl
Injection into the hemolymph of 1.2% NaCl, 11.2% sucrose, 2.3% urea (all
approximately isosmotic to hemolymph), or distilled water induced salivary
fluid secretion in the ixodid tick Amblyomma hebraeum Koch. Saline gave the
largest response at high doses. Injection of hyperosmotic NaCL into the
hemolymph did not induce salivation but led to the drinking of distilled
water in amounts sufficient to dilute the salt load to isosmolarity.
Atropine only partially inhibited salivation induced by NaCl, sucrose, and
distilled water. Reserpine markedly inhibited salivation induced by NaCl.
We propose that at least two sensory pathways (one cholinergic, one not)
converge on the secretory nerve. The physiological significance of the
cholinergic pathway is not known. The other pathway probably mediates the
regulation of hemolymph volume, possibly via stretch receptors, but its
transmitter is not known.
