Summary
Electrical stimulation of the lower brain stem (ESLB) at sites presumed to be parts of the ascending noradrenergic system was carried out in unanaesthetized young guinea pigs. At neutral ambient temperature ESLB elicited a thermogenic response resembling that evoked by microinjection of noradrenaline into the hypothalamus. The response consisted of a rise in oxygen uptake (to more than 50% of the resting value) and of body temperatures, especially of the interscapular adipose tissue. In some cases shivering was also evoked. The thermogenic response to ESLB was completely blocked by additional microinjection of an adrenergic alpha-receptor blocker, phentolamine, into the hypothalamic area where the noradrenergic fibres were presumed to terminate. Subsequent intrahypothalamic injection of noradrenaline, which had formerly been shown to restore the decreased responses to repeated ESLB, failed to restore the effectiveness of ESLB after phentolamine. It is concluded that the thermogenic responses to ESLB are mediated by a noradrenergic pathway ascending to the hypothalamus and not by direct stimulation of efferent pathways controlling the peripheral target system. The hypothalamic transmission can be prevented by an alpha-adrenergic blockade.
Similar content being viewed by others
References
Brück, K., Wünnenberg, W.: Beziehung zwischen Thermogenese im “braunen” Fettgewebe, Temperatur im cervicalen Anteil des Vertebralkanals und Kältezittern. Pflügers Arch. ges. Physiol.290, 167–183 (1966)
Brück, K., Wünnenberg, W.: Eine kälteadaptive Modifikation: Senkung der Schwellentemperaturen für Kältezittern. Pflügers Arch. ges. Physiol.293, 226–236 (1967)
Brück, K., Wünnenberg, W., Gallmeier, H., Ziehm, B.: Shift of threshold temperature for shivering and heat polypnea as a mode of thermal adaptation. Pflügers Arch.321, 159–172 (1970)
Kirpekar, S. M.: Factors influencing transmission at adrenergic synapses. Prog. Neurobiol.4 (3), 163–210 (1975)
Kobayashi, R. M., Palkovits, M., Jacobowitz, D. M., Kopin, I. J.: Biochemical mapping of the noradrenergic projection from the locus coeruleus. Neurology (Minneap.)25, 223–233 (1975)
Lindvall, O., Björklund, A.: The organization of the ascending catecholamine neuron systems in the rat, as revealed by the glyoxylic acid fluorescence method. Acta Physiol.Scand.92, Suppl. 412 (1974)
Roizen M. F.: Biochemical mapping of noradrenergic projections of axons in the dorsal noradrenergic bundle. Brain Res.104, 384 (1976)
Szelényi, Z., Zeisberger, E., Brück, K.: Effects of electrical stimulation in the lower brainstem on temperature regulation in the unanaesthetized guinea pig. Pflügers Arch.364, 123–127 (1976)
Ungerstedt, U.: Stereotaxic mapping of the monoamine pathways in the rat brain. Acta Physiol. Scand.82, 1–48 (1971)
Zeisberger, E., Brück, K.: Central effect of noradrenaline on the control of body temperature in the guinea pig. Pflügers Arch.322, 152–166 (1971)
Zeisberger, E., Brück, K.: Alteration of shivering threshold in cold- and warm-adapted guinea pigs following intrahypothalamic injections of noradrenaline and of an adrenergic alpha-receptor blocking agent. Pflügers Arch.362, 113–119 (1976)
Author information
Authors and Affiliations
Additional information
Supported by the Deutsche Forschungsgemeinschaft SFB 122, Projeckt B 1
Rights and permissions
About this article
Cite this article
Szelényi, Z., Zeisberger, E. & Brück, K. A hypothalamic alpha-adrenergic mechanism mediating the thermogenic response to electrical stimulation of the lower brainstem in the guinea pig. Pflugers Arch. 370, 19–23 (1977). https://doi.org/10.1007/BF00707940
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00707940