Sun Z, Fregly M J, Rowland N E, Cade J R
Department of Physiology, University of Florida, College of Medicine, Gainesville, USA.
Physiol Behav. 1996 Dec;60(6):1543-9. doi: 10.1016/s0031-9384(96)00325-3.
In most forms of experimentally induced hypertension in rats, females develop a less severe form of the disease than males. The objective of the present study was to compare the two genders with respect to the development of cold-induced hypertension. The results of the study indicate that both males and females develop comparable elevations of blood pressure and at approximately the same rate. Thus, the blood pressures of both groups increased significantly within 2 weeks of exposure to cold and reached similar maximal levels by the seventh week. The dipsogenic responsiveness of both groups of cold-exposed rats to acute administration of the peptide hormone, angiotensin II (AngII), was increased to approximately the same extent above that of warm-adapted counterparts, suggesting an increase in the responsiveness to AngII in the brain. To assess this possibility, the induction of the oncogene, cFos, was studied in brain following IV infusion of AngII (333 ng/kg/min). Fos-like immunoreactivity (FLI) was greater (p < 0.01) in subfornical organ, supraoptic and paraventricular hypothalamic nuclei of both cold-exposed groups compared to warm-adapted controls. Thus, both male and female rats have similar elevations of blood pressure as well as increased dipsogenic and FLI responsiveness to administration of AngII during chronic exposure to cold.
在大多数实验诱导的大鼠高血压模型中，雌性大鼠患该病的症状比雄性大鼠轻。本研究的目的是比较雄性和雌性大鼠在冷诱导高血压发展过程中的情况。研究结果表明，雄性和雌性大鼠的血压升高程度相当，且速度大致相同。因此，两组大鼠在暴露于寒冷环境2周内血压均显著升高，并在第7周达到相似的最高水平。两组冷暴露大鼠对急性注射肽类激素血管紧张素II（AngII）的致渴反应性，比适应温暖环境的对照组大鼠提高到大致相同的程度，这表明大脑对AngII的反应性增加。为评估这种可能性，在静脉输注AngII（333 ng/kg/min）后，研究了大脑中癌基因cFos的诱导情况。与适应温暖环境的对照组相比，两组冷暴露大鼠的穹窿下器官、视上核和下丘脑室旁核中的Fos样免疫反应性（FLI）更强（p < 0.01）。因此，在长期暴露于寒冷环境期间，雄性和雌性大鼠的血压升高情况相似，且对注射AngII的致渴和FLI反应性均增加。
