[Relationship between arsenic-induced hypothermia and brain monoamines. (2). The roles of noradrenaline and dopamine].

It has been reported that hypothermia induced by intravenous administration of As2O3 3 mg/kg in rabbits is due to a decrease of noradrenaline (NA) in the hypothalamus. In this paper, the role of NA or dopamine (DA) on As2O3-induced hypothermia in rabbits were investigated. As2O3-induced hypothermia was not inhibited by pretreatment with FLA-63, a potent dopamine-beta-hydroxylase inhibitor, which produces an increase of DA and a decrease of NA in rabbit brain; and it was also inhibited by pretreatment with haloperidol or pimozide, potent DA-receptor blocking agents. On the contrary, pretreatment with phenoxybenzamine or dibenamine, alpha-receptor blocking agents, completely inhibited these hypothermia. These findings indicated that NA took an important part in thermoregulation in rabbits and certified that DA or DA-receptors were not involved As2O3-induced hypothermia.