Electromechanical characteristics of the human colon in vitro: is there any difference between the right and left colon?
OBJECTIVE
We examined the electrical and mechanical characteristics of the smooth muscles in the human colon at the muscle cell, the muscle strip, and at the whole tissue levels


METHODS
Conventional microelectrode recordings and tension recordings were performed.


RESULTS
There was no difference in resting membrane potential, frequency, and amplitude of slow waves between the right and left colon; but there were significant differences in frequency and amplitude of the slow waves between inner circular muscle (CM) and longitudinal muscle (LM), and between inner CM and outer CM, but not between outer CM and LM. On tension recording of CM and LM strip and colonic segment, amplitude, frequency, and area under the curve showed no difference between the right and left colon. In whole colonic segment, high amplitude dominant waves (DW) were found both in CM and LM. Low amplitude non-DWs were detected only in CM, more commonly in right colon and propagated aborally. DWs in the CM were associated with DWs in the LM. In the CM of the left colon, all DWs in the CM propagated aborally ending-up with DW in the LM layer. However, in the right colon, mixed pattern of propagation was detected in adjacent recording sites in 60% of tissues examined.


CONCLUSIONS
Electrophysiologic and mechanical characteristics were similar between the right and left human colon. However, the retrograde propagation of both DWs and non-DWs in the CM was more frequent in the right colon, accounting for mixing function in this region of the human colon.
Choe
Eun Kyung
EK
Department of Surgery, Seoul National University Hospital, 101 Daehangno (28 Yeongeon-dong), Jongno-gu, Seoul 110-774, South Korea. choe523@gmail.com
Moon
Jung Sun
JS
Moon
Suk Bae
SB
So
In-Suk
IS
Park
Kyu Joo
KJ
D003106:Colon / Q000502:physiology*; D055724:Electrophysiological Phenomena; D006801:Humans; D066298:In Vitro Techniques; D042541:Intracellular Space / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009129:Muscle Tonus / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology