Synaptic inhibition of smooth muscles of the human colon: Effects of vitamin B6 and its derivatives |
| |
Authors: | A V Romanenko M M Grusha |
| |
Institution: | (1) Bogomolets National Medical University, Ministry of Public Health of Ukraine, Kyiv, Ukraine |
| |
Abstract: | Spontaneous activity, which is manifested as slow depolarization waves and action potentials, is observed in most (81%) smooth
muscles (SMs) of the circular layer of the human colon. Independently of the type of pathology, inhibitory junction potentials
(IJPs) in SMs of various parts of the human colon are evoked by intramural stimulation; ranges of parameters of these potentials
were comparable with those observed in muscle intestinal fragments isolated at a distance of several tens of centimeters from
the zone of injury. In muscle strips (MSs) of such fragments, pyridoxal-5′-phosphate (PPh) applied in different concentrations
caused suppression of IJPs: in the concentration of 1·10−8 to 1·10−4 M it decreased the amplitude, and in the concentrations of 1·10−5 to 1·10−4 M and 1·10−4 M, respectively, it decreased rates of the half-amplitude rise and decay of these potentials. Pyridoxal (1·10−4 M) and 4-pyridoxolic acid (1·10−4 M) also caused a drop in the amplitude of IJPs; however, these agents influenced this parameter to a lesser extent, as compared
with the effect of 1·10−4 M PPh. Pyridoxine (1·10−4 M) and pyridoxamine (1·10−4 M) evoked no significant changes in the parameters of IJPs in MSs of the human colon. Our data allow us to hypothesize that
the suppressing effect of PPh on IJPs is determined by the presence of a purinergic component present in non-adrenergic inhibition
of SMs of the human colon.
Neirofiziologiya/Neurophysiology, Vol. 38, No. 4, pp. 269–279, July–August, 2006. |
| |
Keywords: | synaptic inhibition smooth muscles human intestine vitamin B6 pyridoxal-5-′ -phosphate |
本文献已被 SpringerLink 等数据库收录! |
|