Summary
The effects of stimulating the pars compacta of the substantia nigra (SNC) on thermoregulation were assessed in normal rats, in rats with chemical lesion of the SNC dopamine (DA) pathways and in rats with striatal DA receptor blockade. Electrical stimulation of the SNC produced hypothermia, decreased metabolism and/or cutaneous vasoconstriction in rats at ambient temperatures (T a ) below 22°C, as well as hyperthermia and cutaneous vasoconstriction in rats at T a of 30°C. Microinjection of an excitotoxic amino acid (kainic acid) at the same brain sites also produced the same thermal responses. In vivo voltammetric studies revealed that electrical or chemical stimulation of the SNC produced an increase in striatal DA release. The enhanced striatal DA release induced by SNC stimulation was attenuated in rats after selective destruction of the nigrostriatal DA pathway by administration of 6-hydroxydopamine into the medial forebrain bundle. In addition, the magnitude of the thermal responses produced by the SNC stimulation in the cold was attenuated by selective bilateral destruction of the nigrostriatal DA pathways or selective blockade of the striatal DA produced by intrastriatal infusion of haloperidol, a DA receptor antagonist. The results indicate that stimulation of the SNC inhibits both heat production and heat loss mechanisms in the rat.
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This study was supported by grants from the National Science Council of the Republic of China
Correspondence to: Mao Tsun Lin at the above address
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Lin, M.T., Ho, M.T. & Young, M.S. Stimulation of the nigrostriatal dopamine system inhibits both heat production and heat loss mechanisms in rats. Naunyn-Schmiedeberg's Arch Pharmacol 346, 504–510 (1992). https://doi.org/10.1007/BF00169004
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DOI: https://doi.org/10.1007/BF00169004