Relationship between Substance P-Induced Initial Transient Contractions and Inositol Phospholipid Hydrolysis in Guinea Pig Ileum

Abstract

The effects of neomycin on substance P (SP)-induced inositol phospholipid hydrolysis and muscle contraction were studied in longitudinal smooth muscle of guinea pig ileum. Various tachykinin peptides including SP stimulated inositol phospholipid hydrolysis in guinea pig ileum. Neomycin (2.5mM) reduced both the contractions and the accumulation of [³H] inositol phosphates induced by SP. These results suggest that the initial transient contractions induced by SP are coupled to inositol phospholipid hydrolysis.