Galluzzi Franco, Menozzi Alessandro, Saleri Roberta, De Rensis Fabio, Spattini Giliola
Castellarano Veterinary Clinic, 42014 Castellarano, Italy.
Department of Veterinary Science, University of Parma, 43126 Parma, Italy.
Vet Sci. 2025 Sep 22;12(9):918. doi: 10.3390/vetsci12090918.
Bethanechol chloride, a nonselective muscarinic agonist, is the most frequently employed drug in dogs and cats to induce detrusor smooth muscle contraction under conditions characterized by poor or absent bladder emptying. Although this drug has minimal or absent nicotinic activity, at higher doses, weak stimulation of neuronal nicotinic receptors may occur, causing the release of noradrenaline, which induces contraction of the urethral smooth muscle by activating α-adrenergic receptors. In the presence of total or partial suprasacral lesions, the elaboration and initiation phase of the urination process is absent due to an interruption of afferent signals from the bladder to the brainstem. In such cases, hypertonicity of the urethral sphincters is expected, and bethanechol is contraindicated. Bethanechol is also not indicated for reflex dyssynergia. In the presence of complete injuries involving the sacral segments, cauda equina, or pelvic nerve, both reflex and voluntary micturition are abolished, and bethanechol is usually ineffective. However, in cases of partial injuries, bethanechol is likely to be effective, as partial integrity of the micturition reflex is required to produce sustained bladder contraction. Bethanechol may benefit patients with myopathic decompensated bladder, although its effectiveness depends on the severity of detrusor damage.
氯化氨甲酰甲胆碱是一种非选择性毒蕈碱激动剂，是犬猫中最常用的药物，用于在膀胱排空不良或无膀胱排空的情况下诱导逼尿肌平滑肌收缩。尽管这种药物的烟碱活性极小或不存在，但在较高剂量时，可能会对神经元烟碱受体产生微弱刺激，导致去甲肾上腺素释放，而去甲肾上腺素通过激活α-肾上腺素能受体诱导尿道平滑肌收缩。在完全或部分骶上损伤的情况下，由于膀胱向脑干的传入信号中断，排尿过程的准备和起始阶段缺失。在这种情况下，预计尿道括约肌会出现高张力，因此禁用氯化氨甲酰甲胆碱。氯化氨甲酰甲胆碱也不适用于反射性协同失调。在涉及骶段、马尾或盆腔神经的完全损伤情况下，反射性和自主性排尿均被废除，氯化氨甲酰甲胆碱通常无效。然而，在部分损伤的情况下，氯化氨甲酰甲胆碱可能有效，因为需要排尿反射的部分完整性才能产生持续的膀胱收缩。氯化氨甲酰甲胆碱可能对患有肌病性失代偿膀胱的患者有益，尽管其有效性取决于逼尿肌损伤的严重程度。
