Abstract
The effect of substance P (SP) on the electrical and contractile responses of skeletal muscles of frog, chick and rat were studied using electrophysiological techniques. In low concentrations, SP (i) increased the amplitude of twitch and tetanic contractions in response to motor nerve stimulation of frog, chick and rat preparations, (ii) increased the amplitude and duration of frog sciatic nerve compound action potential and (iii) reduced the contracture responses produced by acetylcholine (ACh) or tetraethylammonium (TEA) in the chick skeletal muscle. In all these actions, the effect of SP was calcium-dependent. The results provide evidence that SP had a dual action; a prejunctional facilitatory effect by causing a further release of ACh and/or Ca 2+ entry or release, and postjunctional effect by reducing the sensitivity of the postjunctional membrane to depolarizing drugs.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
