Chronic local cold stress to the soles induces hypertension in rats

The purpose of this study was to determine whether cold-stress stimulation to the soles of paws produces continuous hypertension in rats. Wistar–Kyoto rats were kept in cages with a 0°C floor and 23°C room temperature (cold-stressed group, n = 10) or in cages with 23°C floor and 23°C room temperature (control group, n = 10). BP and levels of plasma catecholamines, serum glucose, and serum insulin were measured, and the histologic characteristics of the kidney and adrenal gland were studied in all groups. After a week of localized cold-stress, BP of the experimental rats were significantly increased over those of the control rats. Significant increases were also seen in plasma epinephrine and norepinephrine, as well as serum insulin concentrations in the rats that underwent localized cold stimulation; these changes were not observed in the control rats. Fibrinoid deposition in the kidney and the intensity of neuropeptide Y-staining in the adrenal medulla were increased in the localized cold-stressed group compared with the control group. We conclude that chronic local cold stimulation to the soles is a new model of experimental hypertension.