Nilsson O, Bööj S, Dahlström A, Hargens A R, Millard R W, Pettersson K S
Institute of Neurobiology, University of Göteborg, Sweden.
Blood Vessels. 1988;25(6):299-307. doi: 10.1159/000158743.
The extreme blood pressure gradients in the giraffe, produced by gravity and behaviour, present a special challenge to blood flow and vascular capacity regulation, e.g. via sympathetic nerves. We report the distribution of nerves in vascular tissue from giraffe extremities and neck based on immunofluorescence against specific antisera to dopamine-beta-hydroxylase, neuropeptide Y, neurofilament, and synapsin I. Sympathetic innervation of gravitation-dependent arteries in the limbs was restricted to the adventitia-media border, while in carotid arteries fibers penetrated deep into the media. Surprisingly, limb veins appeared to be devoid of sympathetic innervation, while jugular veins had a sparse innervation. The morphological response, medial hypertrophy, that parallels the hydrostatic pressure gradients in the circulation combines with the thick skin and tight underlying fascia, the 'g-suit', and an exquisitely distributed sympathetic innervation pattern to provide an effective array of mechanisms for cardiovascular regulation in the adult giraffe.
长颈鹿体内由重力和行为产生的极端血压梯度，对血流和血管容量调节提出了特殊挑战，例如通过交感神经进行调节。我们基于针对多巴胺-β-羟化酶、神经肽Y、神经丝和突触素I的特异性抗血清进行免疫荧光检测，报告了长颈鹿四肢和颈部血管组织中神经的分布情况。四肢中依赖重力的动脉的交感神经支配仅限于外膜-中膜边界，而在颈动脉中，纤维深入中膜。令人惊讶的是，四肢静脉似乎没有交感神经支配，而颈静脉的神经支配则很稀疏。与循环中的静水压力梯度平行的形态学反应——中膜肥厚，与厚厚的皮肤和紧绷的深层筋膜（“重力服”）以及分布精妙的交感神经支配模式相结合，为成年长颈鹿的心血管调节提供了一系列有效的机制。
