Viramontes B E, Malcolm A, Camilleri M, Szarka L A, McKinzie S, Burton D D, Zinsmeister A R
Enteric Neuroscience Program, Gastroenterology Research Unit, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.
Am J Physiol Gastrointest Liver Physiol. 2001 Dec;281(6):G1468-76. doi: 10.1152/ajpgi.2001.281.6.G1468.
To characterize alpha(2)-adrenergic control of motor and sensory functions of gastrointestinal tract and colon, we studied dose-related effects of clonidine (placebo or up to 0.3 mg po) by random assignment in 55 healthy humans. Gastrointestinal transit was measured in all subjects; in 35, we assessed colonic compliance, tone, and sensations of gas and pain during phasic distensions. Clonidine did not significantly alter gastrointestinal or colonic transit, but it increased colonic compliance and reduced fasting tone without altering colonic response to a meal. Clonidine significantly reduced aggregate sensation to distensions overall and had significant linear dose-related sensory effects at 8- and 24-mmHg distensions. Effect on pain (including dose-response relationship) was due to 0.3-mg dose for distensions at 24 mmHg. We confirmed that clonidine relaxes fasting colonic tone and reduces sensation of pain. In this study, gut transit was not altered by clonidine, and novel dose-response characteristics and clonidine's effect on gas sensation are provided. Doses as low as 0.05 mg may be effective and potentially useful in reducing colonic tone and gas sensation.
为了明确α₂-肾上腺素能对胃肠道和结肠运动及感觉功能的控制，我们通过随机分配，对55名健康人研究了可乐定（安慰剂或口服高达0.3毫克）的剂量相关效应。对所有受试者测量了胃肠转运；在35名受试者中，我们评估了结肠在阶段性扩张期间的顺应性、张力以及气体和疼痛感觉。可乐定未显著改变胃肠或结肠转运，但增加了结肠顺应性并降低了空腹张力，同时未改变结肠对进餐的反应。可乐定显著降低了总体对扩张的综合感觉，并且在8毫米汞柱和24毫米汞柱扩张时具有显著的线性剂量相关感觉效应。对疼痛的影响（包括剂量-反应关系）是由24毫米汞柱扩张时0.3毫克的剂量所致。我们证实可乐定可放松空腹结肠张力并减轻疼痛感觉。在本研究中，可乐定未改变肠道转运，并提供了新的剂量-反应特征以及可乐定对气体感觉的影响。低至0.05毫克的剂量可能有效，并且在降低结肠张力和气体感觉方面可能有用。
