Immunoneutralization of substance P attenuates the reflex pressor response to muscular contraction.

We previously reported that subarachnoid injection of a peptide antagonist to substance P attenuated by half the reflex pressor response to static muscular contraction. Subsequently, some of the peptide antagonists to substance P have been found to possess local anesthetic effects. Therefore, we have repeated our experiments using a substance P antiserum, which was shown to be without local anesthetic effect. We found that intrathecal injection of the antiserum attenuated by more than half the reflex pressor response to static contraction of the triceps surae muscles of cats.