Stevens L M, Landis S C
Dev Biol. 1987 Sep;123(1):179-90. doi: 10.1016/0012-1606(87)90440-4.
Previous studies suggest that the sympathetic innervation of the sweat glands in the rat is initially noradrenergic and during development undergoes a transition in neurotransmitter phenotype to become cholinergic. To characterize this system and its development further, we have examined the adrenergic and cholinergic components of the secretory response in adult and immature rats and have studied the onset of sweating in the plantar sweat glands of developing rats. Stimulation of the sciatic nerve in adult rats elicited a secretory response which was completely blocked by the cholinergic antagonist, atropine, and was unaffected by adrenergic antagonists, indicating that nerve-evoked secretion was cholinergic. In adult rats, the sweat glands were quite sensitive to cholinergic agonists. In addition to acetylcholine, the mature sweat gland innervation contains vasoactive intestinal peptide (VIP). In some rats, the injection of VIP alone elicited a secretory response which was blocked by atropine, suggesting that the response to VIP was mediated cholinergically. In contrast to cholinergic agonists, the glands responded relatively infrequently and with reduced volumes of sweat to the alpha- and beta-adrenergic agonists 6-fluoronorepinephrine and isoproterenol. However, when VIP, which is a potent vasodilator, was simultaneously injected with adrenergic agonists, glands in many of the injected footpads exhibited a secretory response. The response to adrenergic agonists in combination with VIP was reduced by atropine and by phentolamine plus propranolol, but was blocked completely only by a combination of the three antagonists, indicating that both adrenergic and cholinergic mechanisms were involved. In immature rats, sweating evoked by nerve stimulation first appeared at 14 days of age in 25% of the rats tested. Both the percentage of rats sweating and the number of active glands increased rapidly. At 16 days, 50% of the rats tested exhibited some active glands, and by 21 days all rats tested exhibited a secretory response. In 16-day-old rats, nerve-evoked sweating was almost completely inhibited by local injection of 1 microM atropine, but was unaffected by phentolamine and propranolol in concentrations up to 10 microM. Similarly, the glands were sensitive to 10 microM muscarine, but they exhibited no secretory response to the alpha-adrenergic agonists, clonidine and 6-fluoronorepinephrine, nor to the beta-adrenergic agonist, isoproterenol, at concentrations up to 50 microM. The simultaneous injection of VIP with adrenergic agonists did not reveal an adrenergically mediated secretory response in 16-day-old animals.(ABSTRACT TRUNCATED AT 400 WORDS)
以往的研究表明，大鼠汗腺的交感神经支配最初是去甲肾上腺素能的，在发育过程中神经递质表型会发生转变，变为胆碱能。为了进一步表征这个系统及其发育过程，我们研究了成年和未成年大鼠分泌反应中的肾上腺素能和胆碱能成分，并研究了发育中大鼠足底汗腺出汗的起始情况。刺激成年大鼠的坐骨神经会引发分泌反应，该反应完全被胆碱能拮抗剂阿托品阻断，且不受肾上腺素能拮抗剂的影响，这表明神经诱发的分泌是胆碱能的。在成年大鼠中，汗腺对胆碱能激动剂相当敏感。除了乙酰胆碱外，成熟的汗腺神经支配还含有血管活性肠肽（VIP）。在一些大鼠中，单独注射VIP会引发分泌反应，该反应被阿托品阻断，这表明对VIP的反应是由胆碱能介导的。与胆碱能激动剂不同，汗腺对α-和β-肾上腺素能激动剂6-氟去甲肾上腺素和异丙肾上腺素的反应相对较少，且出汗量减少。然而，当强效血管扩张剂VIP与肾上腺素能激动剂同时注射时，许多注射脚垫中的腺体都会出现分泌反应。肾上腺素能激动剂与VIP联合使用时的反应会被阿托品、酚妥拉明加普萘洛尔降低，但只有三种拮抗剂联合使用时才会完全阻断，这表明肾上腺素能和胆碱能机制都参与其中。在未成年大鼠中，神经刺激诱发的出汗在14日龄时首次出现在25%接受测试的大鼠中。出汗大鼠的百分比和活跃腺体的数量都迅速增加。在16日龄时，50%接受测试的大鼠有一些活跃腺体，到21日龄时，所有接受测试的大鼠都出现了分泌反应。在16日龄大鼠中，局部注射1微摩尔/升阿托品几乎完全抑制了神经诱发的出汗，但浓度高达10微摩尔/升的酚妥拉明和普萘洛尔对其没有影响。同样，腺体对10微摩尔/升毒蕈碱敏感，但在浓度高达50微摩尔/升时，它们对α-肾上腺素能激动剂可乐定和6-氟去甲肾上腺素以及β-肾上腺素能激动剂异丙肾上腺素均无分泌反应。在16日龄动物中，将VIP与肾上腺素能激动剂同时注射并未显示出肾上腺素能介导的分泌反应。（摘要截断于400字）
