Reid I A, Nolan P L, Wolf J A, Keil L C
Endocrinology. 1979 May;104(5):1403-6. doi: 10.1210/endo-104-5-1403.
Studies were performed in anesthetized dogs to determine if the diuretic effect of clonidine results from inhibition of vasopressin secretion. Intravenous clonidine (30 microgram/kg) decreased plasma vasopressin concentration (as measured by RIA) from 10.9 +/- 1.5 to 5.0 +/- 1.1 ng/ml (P less than 0.01) in association with a transient increase in arterial blood pressure and a decrease in heart rate. Intravenous administration of two alpha-adrenoceptor antagonists, piperoxane and phentolamine, virtually abolished the pressor effect of clonidine but did not prevent the suppression of plasma vasopressin concentration. Clonidine decreased plasma vasopressin concentration from 11.9 +/- 3.1 to 3.3 +/- 1.0 pg/ml in the phentolamine-treated dogs (P less than 0.01) and from 18.1 +/- 4.5 to 12.4 +/- 3.6 pg/ml in the piperoxane-treated dogs (P less than 0.05). These results provide direct evidence that the diuretic effect of clonidine results from inhibition of the secretion of vasopressin. This inhibition does not appear to be a consequence of the pressor effect of the drug but may result from a direct action in the central nervous system.
在麻醉犬身上进行了多项研究，以确定可乐定的利尿作用是否源于对血管加压素分泌的抑制。静脉注射可乐定（30微克/千克）可使血浆血管加压素浓度（通过放射免疫分析法测定）从10.9±1.5降至5.0±1.1纳克/毫升（P<0.01），同时伴有动脉血压短暂升高和心率降低。静脉注射两种α-肾上腺素能拮抗剂哌罗克生和酚妥拉明，几乎消除了可乐定的升压作用，但并未阻止血浆血管加压素浓度的降低。在酚妥拉明处理的犬中，可乐定使血浆血管加压素浓度从11.9±3.1降至3.3±1.0皮克/毫升（P<0.01）；在哌罗克生处理的犬中，可乐定使血浆血管加压素浓度从18.1±4.5降至12.4±3.6皮克/毫升（P<0.05）。这些结果提供了直接证据，表明可乐定的利尿作用源于对血管加压素分泌的抑制。这种抑制作用似乎不是药物升压作用的结果，而可能是中枢神经系统直接作用的结果。
