Vasoactivity and immunoreactivity of fish tachykinins in the
vascular system of the spiny dogfish (squalus acanthias).
K[angstrom]agstr[diaeresis]om, J., M. Axelsson, J. Jensen, A. P.
Farrell, and S. Holmgren.
Department of Zoophysiology, G[diaeresis]oteborg University,
Medicinaregatan 18, S-413 90 G[diaeresis]oteborg, Sweden, and Simon
Fraser University, Department of Biological Sciences, Burnaby,
British Columbia V5A 1S6, Canada
APStracts 2:0260R, 1995.
Tachykinin control of gut blood flow (measured by pulsed Doppler
technique), dorsal aortic pressure and heart rate were studied in
unrestrained spiny dogfish, Squalus acanthias, injected with the
elasmobranch tachykinins scyliorhinin I and II (SCY I and SCY II),
and the trout tachykinins substance P (SP) and neurokinin A (NKA).
Effects on somatic vasculature were measured by in vitro perfusion of
the isolated tail. SCY I and trout SP produced hypotension due to a
general vasodilation. This caused a transient increase in mesenteric
blood flow and a prolonged increase in coeliac blood flow. SCY II
caused an initial hypertension induced by a general vasoconstriction,
followed eventually by an elevated flow in both gut arteries due to
dilation of the vascular beds. Trout NKA evoked a short-lasting
increase in coeliac blood flow due to a decrease in vascular
resistance, a late decrease in mesenteric flow due to
vasoconstriction, and no effect on the somatic vasculature. None of
the peptides affected heart rate. The study demonstrates a
significant vasoactive function of fish tachykinins in the vascular
system of an elasmobranch species and, in addition, the occurrence of
tachykinin receptor subtypes. Immunohistochemistry revealed a NKA/SCY
II-like peptide in nerve fibres innervating many vessels, including
the coeliac and the mesenteric arteries, the gastro-intestinal canal
and the heart.
Received 5 May 1995; accepted in final form 11 September 1995.
APS Manuscript Number R276-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.