Day Jarrod, King Brian, Haque Sheikh M, Kellum John M
Department of Surgery, Virginia Commonwealth Medical Center, West Hospital, 15th Floor, West Wing, 1200 Broad St., P.O. Box 980519, Richmond, VA 23298-0519, USA.
Am J Surg. 2005 Nov;190(5):736-8. doi: 10.1016/j.amjsurg.2005.07.012.
The 5-HT3 receptor is a serotonin receptor believed to reside on enteric neurons. However, several studies belie an exclusive neural localization. Our hypothesis is that the 5-HT3 receptor agonist, 2-methyl-5-HT (2Me5HT), induces chloride secretion despite neural blockade, which can be blocked by a 5-HT3 receptor antagonist.
Rat distal colon was stripped of its muscularis, mounted as mucosal sheets in Ussing chambers, and short-circuited. Adjacent sheets were pretreated with 1 micromol/L of the neurotoxin, tetrodotoxin, and incubated with 2Me5HT (50 micromol/L) alone or with a 5-HT3 (0.3 micromol/L ondansetron or 0.3 micromol/L tropisetron) or a 5-HT4 (0.3 micromol/L GR11808) receptor antagonist. Short-circuit current (I(sc)) was measured continuously.
2Me5HT caused an increase in I(sc), which was significantly (P <.01, repeated measures analysis of variance) inhibited by ondansetron (n = 8) and tropisetron (n = 5) but not by GR11808.
A 5-HT3 receptor is present at the mucosal level that mediates chloride secretion by a nonneural pathway.
5-羟色胺3（5-HT3）受体是一种血清素受体，被认为存在于肠神经元上。然而，多项研究表明其定位并非仅限于神经组织。我们的假设是，5-HT3受体激动剂2-甲基-5-羟色胺（2Me5HT）在神经传导被阻断的情况下仍能诱导氯化物分泌，且这种作用可被5-HT3受体拮抗剂阻断。
将大鼠远端结肠的肌层剥离，制成黏膜片并安装在Ussing小室中，然后进行短路处理。相邻的黏膜片先用1微摩尔/升的神经毒素河豚毒素预处理，再单独与2Me5HT（50微摩尔/升）或与5-HT3（0.3微摩尔/升昂丹司琼或0.3微摩尔/升托烷司琼）或5-HT4（0.3微摩尔/升GR11808）受体拮抗剂共同孵育。持续测量短路电流（I(sc)）。
2Me5HT导致I(sc)增加，昂丹司琼（n = 8）和托烷司琼（n = 5）可显著抑制（P <.01，重复测量方差分析），但GR11808无此作用。
黏膜水平存在5-HT3受体，其通过非神经途径介导氯化物分泌。
