Yu J H, Redman R S
Department of Physiology and Biophysics, Georgetown University Medical Center, DC 20007.
Arch Oral Biol. 1992 Dec;37(12):1067-78. doi: 10.1016/0003-9969(92)90039-b.
These effects were examined with and without pretreatment of animals with reserpine and the adrenergic antagonists prazosin (alpha 1), yohimbine (alpha 2) and propranolol (beta). The effects of clonidine on glandular concentrations of norepinephrine and dopamine also were examined. These effects were compared with those of xylazine, a presynaptic alpha 2-adrenergic agonist. A single, high dose of clonidine followed by an overnight fast caused marked increases in calcium content and acinar secretory granules in the submandibular and sublingual glands, similar to those caused by reserpine. However, the calcium content of the parotid gland was not altered by clonidine, although there seemed to be a modest increase in acinar secretory granules. The clonidine-induced increase in submandibular calcium content could not be attributed to any adrenergic receptor activity since it was not blocked by either alpha- or beta-adrenergic antagonists. Unlike reserpine, clonidine did not affect catecholamine concentrations in the parotid and submandibular glands. Pretreatment with reserpine did not significantly alter the clonidine-induced increase in submandibular calcium content. It is likely that the greater accumulation of acinar secretory granules is related to the increased calcium stores of the glands in clonidine- and/or reserpine-treated rats. The large differences in calcium content among the three glands might be attributable, in part, to differences in the calcium-binding capacity of their secretory granules. Possible mechanisms for the clonidine effects on salivary-gland calcium include disturbances in membrane-associated pools or gating mechanisms for calcium, which need further study.
在给动物使用利血平以及肾上腺素能拮抗剂哌唑嗪（α1）、育亨宾（α2）和普萘洛尔（β）进行预处理和不进行预处理的情况下，对这些效应进行了研究。还研究了可乐定对腺体中去甲肾上腺素和多巴胺浓度的影响。将这些效应与突触前α2肾上腺素能激动剂赛拉嗪的效应进行了比较。单次高剂量的可乐定给药后禁食过夜，导致下颌下腺和舌下腺的钙含量以及腺泡分泌颗粒显著增加，类似于利血平所引起的变化。然而，可乐定并未改变腮腺的钙含量，尽管腺泡分泌颗粒似乎有适度增加。可乐定引起的下颌下腺钙含量增加不能归因于任何肾上腺素能受体活性，因为它既未被α-也未被β-肾上腺素能拮抗剂阻断。与利血平不同，可乐定不影响腮腺和下颌下腺中的儿茶酚胺浓度。用利血平预处理并未显著改变可乐定引起的下颌下腺钙含量增加。在可乐定和/或利血平处理的大鼠中，腺泡分泌颗粒的更多积累可能与腺体钙储存增加有关。这三种腺体之间钙含量的巨大差异可能部分归因于它们分泌颗粒的钙结合能力不同。可乐定对唾液腺钙的影响的可能机制包括与膜相关的钙池或门控机制的紊乱，这需要进一步研究。
