Human Humoral Thermogenesis

Janský, L; Vybíral, S; Štich, Vladimír; Šrámek, P.; Kvítek, J.; Lesná, I. Králová; Šimečková, Marie

doi:10.1111/j.1749-6632.1997.tb51768.x

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…Since cold exposure increases blood level of noradrenaline (Janský et al 1996b(Janský et al , 1997Vybíral et al 2000;Krámek et al 2000;Kimebková et al 2000), this approach comes out from the assumption that infusions of adrenergic substances, namely noradrenaline, simulate conditions of cold exposure. This procedure is routinely used to quantify intensity of nonshivering thermogenesis in animals and man (Janský et al 1967;Mejsnar and Janský 1971;Janský 1988;Lesná et al1999).…”

Section: Discussionmentioning

confidence: 99%

“…Since production of adrenaline was not changed during cold water immersions, it may be concluded that all the observed changes were due to action of noradrenaline. Further it was found that repeated exposures to cold water, inducing cold adaptation, did not inXuence blood level of noradrenaline, but lowered that of adrenaline (Janský et al 1996a(Janský et al , 1997Vybíral et al 2000;Krámek et al 2000;Kimebková et al 2000).…”

Section: Introductionmentioning

confidence: 97%

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Modulation of adrenergic receptors and adrenergic functions in cold adapted humans

et al. 2007

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To specify the role of adrenoceptors in mediating adrenergic functions after adaptation of humans to cold, effect of administration of increasing concentrations of beta1 and beta2 adrenomimetics (Dobutamine, Bricanyl) on resting metabolic rate, heart rate, systolic blood pressure, rectal and skin temperatures of control humans and of cold adapted winter swimmers was studied. Increase in metabolic rate, mediated by beta1 and beta2 adrenomimetics, was attenuated after cold adaptation, indicating downregulation of beta1 and beta2 adrenoceptors. Since cold adapted humans have greater capacity of nonshivering thermogenesis, than that mediated by both beta1 and beta2 adrenoceptors, the role of other subtypes of adrenoceptors in mediating nonshivering thermogenesis is anticipated. Heart rate increased after administration of the beta2 agonist, but was not influenced by the beta1 agonist. The significance of beta2 adrenoceptors in mediating heart rate was depressed after cold adaptation. Data indicate that modifications of activity of beta adrenoceptors play crucial role in mechanisms responsible for adaptation of humans to cold.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Modulation of adrenergic receptors and adrenergic functions in cold adapted humans

et al. 2007

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“…We also found that plasma concentration of dopamine was signi®cantly elevated during cold water immersion, while the adrenaline concentration was unchanged. Thus, cardiovascular changes and a part of the metabolic increase in the cold (nonshivering thermogenesis JanskyÂ et al 1997) contributes to the increased production of noradrenaline and dopamine. Changes in cardiovascular functions due to cold water immersion have been discussed in detail in an earlier paper (JanskyÂ et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Human physiological responses to immersion into water of different temperatures

Šrámek

Šimečková

Janský

et al. 2000

European Journal of Applied Physiology

209

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To differentiate between the effect of cold and hydrostatic pressure on hormone and cardiovascular functions of man, a group of young men was examined during 1-h head-out immersions in water of different temperatures (32 degrees C, 20 degrees C and 14 degrees C). Immersion in water at 32 degrees C did not change rectal temperature and metabolic rate, but lowered heart rate (by 15%) and systolic and diastolic blood pressures (by 11 %, or 12%, respectively), compared to controls at ambient air temperature. Plasma renin activity, plasma cortisol and aldosterone concentrations were also lowered (by 46%, 34%, and 17%, respectively), while diuresis was increased by 107%. Immersion at 20 degrees C induced a similar decrease in plasma renin activity, heart rate and systolic and diastolic blood pressures as immersion at thermoneutrality, in spite of lowered rectal temperature and an increased metabolic rate by 93%. Plasma cortisol concentrations tended to decrease, while plasma aldosterone concentration was unchanged. Diuresis was increased by 89%. No significant differences in changes in diuresis, plasma renin activity and aldosterone concentration compared to subjects immersed to 32 degrees C were observed. Cold water immersion (14 degrees C) lowered rectal temperature and increased metabolic rate (by 350%), heart rate and systolic and diastolic blood pressure (by 5%, 7%, and 8%, respectively). Plasma noradrenaline and dopamine concentrations were increased by 530% and by 250% respectively, while diuresis increased by 163% (more than at 32 degrees C). Plasma aldosterone concentrations increased by 23%. Plasma renin activity was reduced as during immersion in water at the highest temperature. Cortisol concentrations tended to decrease. Plasma adrenaline concentrations remained unchanged. Changes in plasma renin activity were not related to changes in aldosterone concentrations. Immersion in water of different temperatures did not increase blood concentrations of cortisol. There was no correlation between changes in rectal temperature and changes in hormone production. Our data supported the hypothesis that physiological changes induced by water immersion are mediated by humoral control mechanisms, while responses induced by cold are mainly due to increased activity of the sympathetic nervous system.

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