Involvement of nitric oxide in the inhibitory innervation of the
urinary bladder of the atlantic cod, gadus morhua.
Olsson, Catharina, Susanne Holmgren.
Department of Zoophysiology, G[diaeresis]oteborg University,
Medicinaregatan 18, S-413 90 G[diaeresis]oteborg Sweden
APStracts 3:0002R, 1996.
The aim of this study was to investigate the involvement of nitric
oxide (NO) in the non-adrenergic, non-cholinergic (NANC) relaxation
of the urinary bladder of the Atlantic cod, Gadus morhua. NADPH
diaphorase reactive nerve cells, presumed to be able to produce NO,
were found in the vesicular nerve. The cells occurred alone and in
ganglia together with stained and unstained cells. The effect of
inhibitors of NO synthesis on the relaxation was examined in vitro in
isolated muscle preparations. NG-nitro-L-arginine methylester (L
-NAME, 10-4 M) and NG-nitro-L-arginine (L-NOARG, 10-4 M) decreased the
electrically induced relaxation to 32 +/- 6% (n = 8) and 28 +/- 6% (n
= 8) of the control, respectively. L-arginine (10-3 M) increased the
relaxation to 152 +/- 24% (n = 8) without affecting the inhibition by
L-NOARG. The [beta]-adrenoceptor antagonist propranolol together with
L-arginine analogues abolished the relaxation in 7 of 11
preparations. The NO donor sodium nitroprusside (NaNP) caused a
concentration-dependent relaxation of the bladder with a maximal
effect obtained at 10-4 M. LY 83583 (10-5 M), a guanylate cyclase
inhibitor, decreased both the electrically (n = 8) and the NaNP (10-6
M, n = 9) induced relaxation to 69 +/- 5% and 20 +/- 4% of the
control respectively. Together these findings suggest that NO is
involved in the NANC regulation of the motility of the urinary
bladder of the Atlantic cod.
Received 22 August 1995; accepted in final form 13 December 1995.
APS Manuscript Number R526-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96