Even through substance P has been known to stimulate colonic motility in experimental animals, its effects on the human colon have not been intensively studied because of possible toxicity. Thus, the present investigation was performed to observe
effects of substance P on human colon motility by using the ex-vivo isolated human colon. The colon was isolated from patients with colon cancer immediately after surgery. The isolated colon was perfused with modified Krebs' ringer solution at a
fixed
flow rate through a mesenteric artery. Change of intraluminal pressure was recorded on Beckman Dynography R411 recorder connected with a side-hole perfused tube and amicrocapillary infusion system.
In the control group(modified Krebs' Ringer solution only), the frequency of contraction was 3.30±1.16 cycle/10 min on the proximal site, 3.50±1.08 cycle/10 min on the middle site, 3.00±0.67 cycle/10 min on the distal site. The mean duration
of
contraction was 22.27±6.00 sec/cycle on the proximal site, 23.99±8.10sec/cycle on the middle site, 26.56±9.05 sec/cycle on the distal site. The mean amplitude of contraction was 29.16±7.99 cmH2O/cycle on the distal site. Peristaltic
contractions
occurred 77.14±19.29% of all contractions.
After the administered after tetrodotoxin injection, organized and peristaltic contractions restored immediately. The frequency of conctraction was 2.50±0.53 cycle/10 min on the proxima site, 2.50±0.71 cycle/10 min on the middle site,
2.69±0.70
cycle
/10 min on the distal site. The duration of contraction was 27.52±7.15 sec/cycle on the proximal site, 28.08±9.22 sec/cycle on th middle site, 31.97±9.22 sec/cycle on the middle site, 31.97±10.86 sec/cycle on the distal site. The amplitude of
contraction was 22.18±5.90 cmH2O/cycle on the proximal site, 23.55±3.72 cmH2O/cycle on the middle site, 29.42±5.91 cmH2O/cycle on the distal site. Peristaltic contractions occurred 76.00±29.52% of all contractions.
The experimental results indicate that 1) tetrodotoxin injected through the mesenteric artery vainshed contraction of ex-vivo human colon, 2) and substance P restored the contraction and peristalsis that was vanished by tetrodotoxin in the
ex-vivo
isolated human colon.
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