Yu J H, Mark M R, Redman R S
Georgetown University School of Dentistry, Washington, DC 20007.
Arch Oral Biol. 1987;32(1):27-33. doi: 10.1016/0003-9969(87)90150-6.
Secretion in response to this alpha 2-adrenergic agonist was evaluated in the presence and absence of several adrenergic antagonists, reserpine and sympathectomy (Sx). In both glands, the response was qualitatively but not quantitatively similar to that induced by the alpha 1-adrenergic agonist, phenylephrine, in the presence of propranolol. With clonidine, the volume of submandibular saliva was much higher but the Ca concentration was 3-4 times lower than that of the parotid; both salivas had low Na but high K concentrations. Clonidine-induced secretion was almost completely blocked by the alpha 1-adrenergic antagonist, prazosin and a mixed alpha-adrenergic antagonist, phentolamine, and markedly reduced by the alpha 2-adrenergic antagonist, yohimbine, but unaffected by the beta-adrenergic antagonist, propranolol. Reserpine reduced the parotid, but enhanced the submandibular secretory response to clonidine. Results in Sx glands were similar. Thus, in the rat glands clonidine may activate alpha 1-rather than alpha 2-adrenoceptors, which appear to play a part similar to alpha 1-adrenoceptors only after reserpine or Sx.
在存在和不存在几种肾上腺素能拮抗剂、利血平和交感神经切除术（Sx）的情况下，评估了对这种α2肾上腺素能激动剂的分泌情况。在两个腺体中，在普萘洛尔存在的情况下，该反应在性质上但在数量上与α1肾上腺素能激动剂去氧肾上腺素诱导的反应相似。使用可乐定时，颌下唾液的量要高得多，但钙浓度比腮腺低3 - 4倍；两种唾液的钠浓度低但钾浓度高。可乐定诱导的分泌几乎完全被α1肾上腺素能拮抗剂哌唑嗪和一种混合α肾上腺素能拮抗剂酚妥拉明阻断，并被α2肾上腺素能拮抗剂育亨宾显著降低，但不受β肾上腺素能拮抗剂普萘洛尔的影响。利血平降低了腮腺对可乐定的分泌反应，但增强了颌下腺的分泌反应。交感神经切除腺体的结果相似。因此，在大鼠腺体中，可乐定可能激活α1而非α2肾上腺素能受体，而α2肾上腺素能受体似乎仅在利血平或交感神经切除术后才发挥与α1肾上腺素能受体类似的作用。
