Neurotensin Enhances Gastric Motility in Antral Circular Muscle Strip of Guinea-pig
Neurotensin Enhances Gastric Motility in Antral Circular Muscle Strip of Guinea-pig
- Tae Yong Koh Sung Joon Kim Sang Jin Lee Tong Mook Kang Jae Yeoul Jun Jae Hoon Sim Insuk So Ki Whan K
- 대한생리학회-대한약리학회
- The Korean Journal of Physiology & Pharmacology
- 제4권 제3호
- 등재여부 : KCI등재
- 2000.01
- 227 - 234 (8 pages)
<P> Many reports suggest that neurotensin (NT) in the gastrointestinal tract may play a possible role as a neurotransmitter, a circulating hormone, or a modulator of motor activity. NT exerts various actions in the intestine; it produces contractile and relaxant responses in intestinal smooth muscle. This study was designed to investigate the effect of NT on motility of antral circular muscle strips in guinea-pig stomach. To assess the role of Ca<SUP>2⁢</SUP> influx in underlying mechanism, slow waves were simultaneously recorded with spontaneous contractions using conventional intracellular microelectrode technique. At the concentration of 10<SUP>⁣7</SUP> M, where NT showed maximum response, NT enhanced the magnitude (863⁑198%, mean⁑SEM, n=13) and the frequency (154⁑10.3%, n=11) of spontaneous contractions. NT evoked a slight hyperpolarization of membrane potential, tall and steep slow waves with abortive spikes (278⁑50%, n=4). These effects were not affected by atropine (2μM), guanethidine (2μM) and tetrodotoxin (0.2μM). NT-induced contractile responses were abolished in Ca<SUP>2⁢</SUP>-free solution and reduced greatly to near abolition by 10μM of verapamil or 0.2 mM of CdCl<SUB>2</SUB>. Verapamil attenuated the effects of NT on frequency and amplitude of the slow waves. Taken together, these results indicate that NT enhances contractility in guinea-pig gastric antral circular muscle and Ca<SUP>2⁢</SUP> influx through the voltage-operated Ca<SUP>2⁢</SUP> channel appears to play an important role in the NT-induced contractile mechanism.