Release of calcitonin gene-related peptide-like immunoreactive substance from neuromuscular junction by nerve excitation and its action on striated muscle.
In a rat phrenic nerve-hemidiaphragm preparation, calcitonin gene-related peptide (CGRP) increased the twitch contraction induced by nerve or transmural stimulation dose dependently. Either electrical or high K+ stimulation of the phrenic nerve caused release of a CGRP-like immunoreactive substance (CGRP-LIS) in a Ca2(+)-dependent manner. Electrical stimulation of the phrenic nerve also increased the cyclic AMP content in diaphragm. This increase was not observed in Ca2(+)-free medium and was blocked by antiserum against CGRP. These results indicate that excitation of the motor nerve causes release of CGRP-LIS at nerve terminals and that the released CGRP-LIS increases the cyclic AMP content of skeletal muscles and potentiates twitch contraction.
Uchida
S
S
Department of Pharmacology I, Medical School, Osaka University, Japan.
Yamamoto
H
H
Iio
S
S
Matsumoto
N
N
Wang
X B
XB
Yonehara
N
N
Imai
Y
Y
Inoki
R
R
Yoshida
H
H
D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism* / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D003964:Diaphragm / Q000378:metabolism; D004558:Electric Stimulation; D007158:Immunologic Techniques; D008297:Male; D009119:Muscle Contraction; D009132:Muscles / Q000502:physiology*; D009469:Neuromuscular Junction / Q000378:metabolism*; D010791:Phrenic Nerve / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains
D000242:Cyclic AMP; D015740:Calcitonin Gene-Related Peptide