RT Journal Article
SR Electronic
T1 Pituitary adenylate cyclase activating peptide regulates neurally mediated airway responses
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 64
OP 70
DO 10.1183/09031936.98.12010064
VO 12
IS 1
A1 M Shigyo
A1 H Aizawa
A1 H Inoue
A1 K Matsumoto
A1 S Takata
A1 N Hara
YR 1998
UL http://erj.ersjournals.com/content/12/1/64.abstract
AB To clarify the protective effects of pituitary adenylate cyclase activating peptide (PACAP) on airway narrowing, we examined the effects of PACAP on smooth muscle contraction and plasma extravasation in guinea-pig airways. Smooth muscle contraction evoked by electrical field stimulation (EFS) or exogenously applied acetylcholine (ACh) or substance P (SP) was measured before and after PACAP in vitro. The effect of PACAP on airway plasma extravasation was also measured in vivo. In trachea, PACAP (10(-9) - 10(-7) M) significantly suppressed smooth muscle contraction evoked by EFS without affecting ACh sensitivity, suggesting that PACAP inhibits cholinergic neuroeffector transmission. In the main bronchi, PACAP (10(-9) - 10(-8) M) significantly suppressed the contraction evoked by EFS without affecting SP sensitivity in the presence of atropine, suggesting that PACAP inhibits SP release from excitatory nonadrenergic noncholinergic (eNANC) nerves. In animals treated with atropine and propranolol, PACAP attenuated the increase in plasma extravasation induced by electrical vagus stimulation or by SP. These results suggest that pituitary adenylate cyclase activating peptide may play a role in modulation of airway responses through inhibition of cholinergic and noncholinergic mechanisms.