Warner A, Mayhew I G
Vet Res Commun. 1983 Sep;6(4):249-64. doi: 10.1007/BF02214921.
Anhidrosis is loss of the ability to sweat. The problem is seen in horses kept in a hot humid climate, and it may cause severe impairment of thermoregulation in the equine athlete. British Thoroughbreds imported to her tropical colonies are the earliest recorded cases, and since then the syndrome has come to be described as one of Thoroughbreds, usually performance athletes, undergoing acclimatization to heat and humidity. A recent epidemiologic study of cases in Florida has shown, however, that many different breeds, and long time inhabitants of a hot climate, may be affected. Equine sweat glands are of the apocrine type, and sweating is stimulated by direct local release of epinephrine from adrenergic nerve endings and by circulating epinephrine. Lack of sweating could be due to a number of possible flaws in a sequence from central nervous stimulation through sweat stimulation and secretion to delivery of sweat to the skin surface. The most likely possibilities are inadequate sweat gland response due to habituation of receptors to a high circulating level of epinephrine and occlusion of the sweat ducts by keratin plugs. Hormonal or metabolic imbalance may play a role both in the onset and secondary signs associated with anhidrosis.
无汗症是指出汗能力丧失。这种问题在饲养于炎热潮湿气候中的马匹身上可见，它可能会严重损害马类运动员的体温调节能力。被引进到她的热带殖民地的英国纯种马是最早有记录的病例，从那时起，这种综合征就被描述为纯种马（通常是竞技运动员）在适应炎热和潮湿环境时出现的一种情况。然而，最近一项针对佛罗里达州病例的流行病学研究表明，许多不同品种以及长期生活在炎热气候中的马匹都可能受到影响。马的汗腺属于顶泌汗腺类型，出汗是由肾上腺素能神经末梢直接局部释放肾上腺素以及循环中的肾上腺素刺激引起的。不出汗可能是由于从中枢神经刺激到出汗刺激、分泌再到汗液输送到皮肤表面这一过程中存在许多可能的缺陷。最有可能的原因是由于受体对高循环水平的肾上腺素产生适应性而导致汗腺反应不足，以及角质栓堵塞汗腺导管。激素或代谢失衡可能在无汗症的发病及相关继发症状中都起作用。
