阿托品、哌仑西平、可乐定和吗啡对大鼠胃底对场刺激的双相反应的影响。

Effects of atropine, pirenzepine, clonidine, and morphine on biphasic response of rat gastric fundus to field stimulation.

Dehpour A R, Delfan A, Mousavizadeh K, Mortazavi S R

Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Iran.

Gen Pharmacol. 1994 Sep;25(5):951-5. doi: 10.1016/0306-3623(94)90102-3.

Abstract

Electrically evoked contractions in isolated strips of rat gastric fundus were inhibited by atropine (IC50 = 2.5 x 10(-9) M), pirenzepine (IC50 = 2.3 x 10(-8) M), clonidine (IC50 = 3.9 x 10(-8) M) and morphine (IC50 = 3.2 x 10(-7) M) in a dose-dependent manner. 2. The inhibitory effect of morphine was antagonized by naloxone (10(-6) M). The inhibitory effect of clonidine not only was not reversed by yohimbine but also was enhanced. Yohimbine per se inhibited these contractions (IC50 = 6.4 x 10(-6) M). 3. In presence of atropine (2 x 10(-6) M) and guanethidine (5 x 10(-6) M), electrical stimulation of isolated strips of rat gastric fundus produced a non-adrenergic, non-cholinergic (NANC) inhibitory response. 4. The NANC inhibitory response was decreased by morphine (10(-8)-3 x 10(-6) M). In addition, morphine decreased the tone of the muscle. These effects of morphine was antagonized by naloxone (3 x 10(-6) M). 5. Clonidine up to 10(-6) M had no influence on the NANC inhibitory response but yohimbine per se (10(-7)-3 x 10(-5) M) blocked it (IC50 = 3 x 10(-6) M). 6. These findings indicate that electrically evoked contractions in the rat gastric fundus were mediated by muscarinic receptors. In addition, the NANC inhibitory response in the isolated 5-strips of rat gastric fundus was blocked by morphine and yohimbine.

摘要

阿托品（IC50 = 2.5×10⁻⁹ M）、哌仑西平（IC50 = 2.3×10⁻⁸ M）、可乐定（IC50 = 3.9×10⁻⁸ M）和吗啡（IC50 = 3.2×10⁻⁷ M）可剂量依赖性地抑制大鼠胃底离体条带的电诱发收缩。2. 纳洛酮（10⁻⁶ M）可拮抗吗啡的抑制作用。可乐定的抑制作用不仅未被育亨宾逆转，反而增强。育亨宾本身可抑制这些收缩（IC50 = 6.4×10⁻⁶ M）。3. 在阿托品（2×10⁻⁶ M）和胍乙啶（5×10⁻⁶ M）存在的情况下，电刺激大鼠胃底离体条带可产生非肾上腺素能、非胆碱能（NANC）抑制反应。4. 吗啡（10⁻⁸ - 3×10⁻⁶ M）可降低NANC抑制反应。此外，吗啡可降低肌肉张力。纳洛酮（3×10⁻⁶ M）可拮抗吗啡的这些作用。5. 高达10⁻⁶ M的可乐定对NANC抑制反应无影响，但育亨宾本身（10⁻⁷ - 3×10⁻⁵ M）可阻断该反应（IC50 = 3×10⁻⁶ M）。6. 这些发现表明，大鼠胃底的电诱发收缩由毒蕈碱受体介导。此外，吗啡和育亨宾可阻断大鼠胃底离体条带的NANC抑制反应。