Mahe L, Chapelain B, Neliat G, Gargouil Y M
Laboratoire Celaster, BP1 Celle l'Evescault, Luisgnan, France.
Eur J Pharmacol. 1989 Aug 11;167(1):31-9. doi: 10.1016/0014-2999(89)90744-9.
The role of postsynaptic adrenoceptors in the spontaneous activity of isolated bovine mesenteric lymphatic vessels was characterized. Low concentrations of noradrenaline (less than 10(-6) M) increased the amplitude and the frequency of the spontaneous contractions whereas high concentrations (less than 10(-6) M) depressed the activity. beta-Adrenoceptor blockade with propranolol enhanced the stimulation by noradrenaline and suppressed the inhibition. alpha 1-Blockade by prazosin or alpha 2-blockade by idazoxan antagonized the stimulation by noradrenaline and potentiated the inhibition. Activation of alpha 1-adrenoceptors by methoxamine, or of alpha 2-adrenoceptors by clonidine, stimulated lymphatic activity. The increases in the amplitude and frequency of the spontaneous contractions produced by each agonist were competitively antagonized by prazosin and idazoxan, respectively. Our results confirm the presence of postjunctional beta-, alpha 1-and alpha 2-adrenoceptors in lymphatic vessels and show that each of these receptors plays an important role in the adrenergic regulation of the spontaneous activity, with beta-adrenoceptors mediating inhibition, and alpha 1- and alpha 2-adrenoceptors mediating stimulation.
研究了突触后肾上腺素能受体在离体牛肠系膜淋巴管自发活动中的作用。低浓度去甲肾上腺素（低于10⁻⁶ M）可增加自发收缩的幅度和频率，而高浓度（高于10⁻⁶ M）则抑制活动。普萘洛尔阻断β肾上腺素能受体增强了去甲肾上腺素的刺激作用并抑制了抑制作用。哌唑嗪阻断α₁肾上腺素能受体或咪唑克生阻断α₂肾上腺素能受体可拮抗去甲肾上腺素的刺激作用并增强抑制作用。甲氧明激活α₁肾上腺素能受体或可乐定激活α₂肾上腺素能受体可刺激淋巴管活动。每种激动剂引起的自发收缩幅度和频率增加分别被哌唑嗪和咪唑克生竞争性拮抗。我们的结果证实淋巴管中存在节后β、α₁和α₂肾上腺素能受体，并表明这些受体各自在肾上腺素能调节自发活动中起重要作用，其中β肾上腺素能受体介导抑制，α₁和α₂肾上腺素能受体介导刺激。
