AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 1 221-R227, Copyright © 1994 by American Physiological Society
Modulation of rate at which serotonin-induced contraction decays in guinea pig trachea
R. R. Ben-Harari, B. A. Dalton and U. C. Garg
Department of Anesthesiology, New York University Medical Center, New York 10016.
Stimulation of the type 2 serotonin (5-HT2) receptor in guinea pig trachea
with 5-HT results in a contraction that decays in the continued presence of
5-HT. The decay of the 5-HT contraction has been proposed to be dependent
on 5-HT2 receptor activation and to reflect desensitization of the
receptor. The characteristics of the decay of the 5-HT contraction may also
be dependent on other properties of the tissue. The effects of modulation
of biochemical pathways implicated in airway smooth muscle contraction on
the 5-HT contraction in isolated guinea pig trachea were determined with
the use of a kinetic approach we developed previously. Decay of the 5-HT
contraction was inhibited by cooling, increased by forskolin,
3-isobutylmethyl-1-xanthine, and 8-bromoadenosine 3',5'-cyclic
monophosphate, and unaffected by staurosporine, H-7, H-8, phorbol
12,13-dibutyrate, and by inhibitors of the three major pathways of
arachidonic metabolism. The results suggest that decay of the 5-HT
contraction in guinea pig trachea is dependent on both the receptor and the
biochemical state of the tissue.
