Neurokinin A suppresses a voltage-gated K+ current in smooth muscle cells from rat vas deferens.
The effects of neurokinin A (NKA) on freshly isolated smooth muscle cells from the rat vas deferens were investigated electrophysiologically. NKA (10(-7) M) prolonged the duration of action potentials without affecting resting potentials. Under voltage-clamp conditions, NKA (10(-7) M) suppressed an outward K+ current activated by depolarizing voltage steps. Substance P (SP, 10(-7) M) did not affect the K+ current, suggesting that NKA is more potent in suppressing the K+ current than SP is, as is also true for the contractions of smooth muscles of the rat vas deferens. The suppression of the K+ conductance now reported may contribute to NKA-induced smooth muscle contraction.
Nakazawa
K
K
Division of Pharmacology, National Institute of Hygienic Sciences, Tokyo, Japan.
Inoue
K
K
Fujimori
K
K
Takanaka
A
A
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004594:Electrophysiology; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D015288:Neurokinin A / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects
D015221:Potassium Channels; D013373:Substance P; D015288:Neurokinin A