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Responses of 50 olfactory bulb neurons of the bullfrog to odorous solutions of ethyl n-butyrate were composed mainly of facilitation, inhibition and no response, whereas those of the same neurons to water were mainly of facilitation and delayed facilitation. The responses to water tended to continue longer than those to the odorous solutions.

In an attempt to examine chronic effects of toluene on sleep, spontaneous locomotor activity and drinking behavior, rats were repeatedly administered toluene i.p. at doses of 100 and 200 mg/kg body weight for 14 consecutive days. The 200-mg/kg injections induced a decrease in total sleep on Day 1, an increase in locomotor activity on Days 1 through 4 and an increase in drinking activity on Days 0 through 6 after discontinuation of the daily injections. Both the reduced sleep and the increased locomotor activity appeared during the light period, whereas the drinking activity increased during the dark period. In order to find neurochemical correlates of the toluene-induced changes in behavior, regional concentrations of brain monoamines and their metabolites were determined. The toluene-induced partial insomnia and hyperactivity were associated with lowered concentrations of serotonin in frontal cortex, hippocampus and midbrain and 5-hydroxyindoleacetic acid in midbrain and hypothalamus. The increased drinking activity was associated with increased concentrations of striatal 3,4-dihydroxy-phenylacetic acid and homovanillic acid and hypothalamic noradrenaline and 3-methoxy-4-hydroxyphenylethyleneglycol. Central monoaminergic mechanisms were implicated in the toluene-induced partial insomnia, hyperactivity and hyperdipsia.