Nonadrenergic Noncholinergic Nerve-mediated Contraction of the Longitudinal Muscle of Rat Ileum

Kim, Tae-wan; La, Jun-ho; Sung, Tae-sik; Kang, Jung-woo; Yang, Il-suk; Han, Ho-jae

Korean Journal of Veterinary Research 2003;43(3):405-414.

Tae-wan Kim¹, Jun-ho La², Tae-sik Sung², Jung-woo Kang², Il-suk Yang², Ho-jae Han¹

¹College of Veterinary Medicine, Biotechnology Research Institute, Chonnam National University
²College of Veterinary Medicine, Seoul National University

랫드 회장 종주근의 비아드레날린 비콜린성 신경에 의한 수축반응

김태완¹, 나준호², 성태식², 강정우², 양일석², 한호재¹

¹전남대학교 수의과대학 생리학교실/생물공학연구소
²서울대학교 수의과대학 생리학교실

Abstract

The purpose of this study was to assess the role of tachykinins (TK) in mediating nonadrenergic noncholinergic (NANC) contractions produced by electrical field stimulation (EFS) in the longitudinal muscle of the rat ileum. In the presence of atropine ($1{mu}M$), guanethidine ($5{mu}M$), and L-nitroarginine (L-NNA, $200{mu}M$), EFS (0.5ms pulse duration, 120 V, 1-20 Hz for 2 min) produced a frequency-dependent slowly-developing tonic contraction with superimposed phasic contractions ('on'-contraction) followed by off slowly-decreasing tonic and superimposed phasic contractions ('off'-contraction) of mucosa-free longitudinal oriented muscle strip. These EFS induced responses were blocked by tetrotoxin. $NK_1$ receptor selective antagonist L-732,138 strongly inhibited the EFS-induced excitatory responses. However $NK_2$ receptor selective antagonist, GR 159897 and $NK_3$ receptor selective antagonist SB 222200 did not significantly inhibited the responses. $NK_1$ receptor selective agonist [$Sar^9$,$Met(O_2)^{11}$] Substance P and $NK_2$ receptor selective agonist [${eta}-Ala^8$]-neurokinin A (4-10) induced tonic contraction with superimposed phasic contractions of longitudinal oriented muscle strip and almost blocked by selective antagonist L-732,138 and GR 159897, respectively. But $NK_3$ receptor selective agonist senktide did not showed any effect. Nifedipine ($1{mu}M$) abolished the contraction produced either by EFS or by the TK receptor agonists [$Sar^9$,$Met(O_2)^{11}$] Substance P or [${eta}-Ala^8$]-neurokinin A (4-10). It is concluded that, in the longitudinal muscle of rat ileum, both $NK_1$ and $NK_2$ receptors modulated the responses to exogenous tachykinins, whereas $NK_1$ is mainly involved in NANC neuromuscular contraction.

Key Words: rat ileum, nonadrenergic noncholinergic (NANC), tachykinin, electrical field stimulation (EFS)