Feeble bronchomotor responses in diabetic rats in
association with decreased sensory neuropeptide release.
Szilvássy, Judith, István Sziklai, Peter Horvath, Maria
Szilasi, József Németh, Péter Kovács, and Zoltán Szilvássy.
Departments of 1Oto-rhino-laryngology, 3Pulmonology,
5Clinical Pharmacology, and 2Pharmacology, Medical
University of Debrecen, H-4032 Debrecen; and 4Neuroscience
Research Group, University Medical School of Pécs, H-7643
APStracts 9:0027L, 2002.
Type I diabetes is associated with a low incidence of
asthma. We tested whether a decrease in sensory
neuropeptide release is associated with an attenuated
bronchoconstrictive response to field stimulation (FS; 100
stimuli, 20 V, 0.1 ms, 20 Hz) in streptozotocin (STZ)-
induced diabetes. The organ fluid of the preparations were
also tested for substance P, calcitonin gene-related
peptide (CGRP), and somatostatin concentrations by RIA.
Preparations were from either normal rats or those
pretreated with 50 mg/kg STZ iv 8 wk before experiment. A
group of STZ-treated animals was supplied with insulin
delivery (4 IU/day sc) implants between 4 and 8 wk. A
subgroup was formed to study the effect of capsaicin
desensitization. The atropine-resistant contraction was
attenuated by diabetes without capsaicin-sensitive
relaxation response. Exogenous CGRP and substance P
potentiated, whereas somatostatin inhibited (1 nM-10 µM)
the FS-induced contractions in rings from either group. FS
released somatostatin, CGRP, and substance P from 0.17 ±
0.024, 0.15 ± 0.022, and 1.65 ± 0.093 to 0.58 ± 0.032, 0.74
± 0.122, and 5.34 ± 0.295 in preparations from normal, and
from 0.19 ± 0.016, 0.11 ± 0.019, and 0.98 ± 0.116 to 0.22 ±
0.076, 0.34 ± 0.099, and 1.84 ± 0.316 fmol/mg wet wt in
preparations from diabetic rats. Insulin supplementation
restored neuropeptide release in rings from STZ-treated
rats. The results show that the decreased FS-induced
contractions occurred with a decrease in sensory
neuropeptide release in STZ-diabetic rats.
Received 4 December 2000; accepted in final form 29 October 2001
APS Manuscript Number L409-0.
Article publication pending Am J Physiol Lung Cell Mol Physiol
ISSN 1080-4757 Copyright 2002 The American Physiological Society.
Published in APStracts on 28 February 2002