Journal of Applied Physiology, Vol 72, Issue 6 2157-2161, Copyright © 1992 by American Physiological Society
Anesthetic effects on pulmonary allergic responses in rats: changes in sensitivity to serotonin
R. Sorkness, J. Clough, M. Ritter and R. F. Lemanske Jr
Department of Medicine, University of Wisconsin, Madison 53792.
Subsequent to observations that pulmonary responses to antigen challenge
are of different magnitudes in sensitized rats that are anesthetized with
different drugs, we conducted studies to test whether the alterations in
responses were due to changes in airway responsiveness to cholinergic or
serotonergic challenge, opioid-receptor mediated events, or changes in mast
cell mediator release. Immunoglobulin E-sensitized rats anesthetized with
ketamine/urethan had larger changes in lung resistance and plasma histamine
after pulmonary antigen challenge compared with rats anesthetized with
fentanyl-droperidol. Blockade of opioid receptors with naloxone did not
affect the responses. In unsensitized rats, airway responses to aerosolized
methacholine were similar for the two anesthetics, indicating unchanged
smooth muscle responsiveness; however, airway responses to intravenous
serotonin were enhanced by ketamine and ablated by droperidol. We conclude
that ketamine- and droperidol-induced alterations of pulmonary allergic
responses are due to changes in sensitivity to serotonin and in mast cell
mediator release. We speculate that mast cell mediator release may be
modulated by a serotonin receptor-linked mechanism.
