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Biomedical subjects

D G Stein

Publications and source records attributed to D G Stein.

At least 91 records · Page 5Linked to original sources
PubMed1979

Nerve growth factor: effects on D-amphetamine-induced activity and brain monoamines.

Adult male rats were given 6-hydroxydopamine lesions of the nucleus accumbens, followed immediately by injections of saline or nerve growth factor (NGF; 125 B.U.) near the substantia nigra. Such lesions were previously reported to attenuate the locomotor response to D-amphetamine. NGF-treated rats showed an enhanced response to D-amphetamine (1.5 mg/kg) when tested 15 days postoperatively. Levels of dopamine and norepinephrine in the striatum and nucleus accumbens were equivalently depressed in the two lesion groups, indicating that the apparent recovery of the NGF-treated rats was probably not due to catecholaminergic neuronal regrowth. Intracerebral NGF administeration enhanced the response to D-amphetamine 15 days later in rats without lesions, and also appeared to result in increased turnover of brain norepinephrine and serotonin at 3, but not 15, days postadministration. NGF might increase dopamine turnover at 15 days, but the evidence obtained did not convincingly confirm or negate this possibility. The results in brain-damaged and intact rats, and also modify the apparent turnover of brain monoamines.

Animals↗
PubMed1976

Effects of one-stage or serial transections of the lateral olfactory tracts on behavior and plasma testosterone levels in male hamsters.

Bilateral transections of the later olfactory (LOT) in male hamsters at the rostral border of the olfactory tubercle or anterior to the tubercle produced severe deficits in mounting, scent marking, food hoarding and nesting behaviors. There were no impairments of these behaviors following unilateral transections. Cutting of the LOT in two stages, and provision of additional experience in sexual and territorial behaviors during the interval between the first and second transection, did not alleviate the behavioral deficits. Impairments in mounting and scent marking were dissociated in some subjects, indicating individual differences in the hamsters' dependence on chemosensory cues for the regulation of these two types of social behavior. It is suggested that the apparent sparing of behavioral function which has been associated with gradual destruction of nervous tissue is due to the development of alternate mechanisms of response to environmental cues, and may be more difficult when brain damage is in structures which initially process these cues. Although sexual and territorial behaviors in the hamster are dependent on gonadal hormones, the observed impairments of these behaviors could not be explained as indirect consequences of lesion effects on the hypophysiogonadal axis. Circulating testosterone (T) levels in experimental subjects were not different from levels in control (sham-operated) subjects. An inverse correlation was observed between the control subjects' circulating T levels and their incidence of scent marking. A similar correlation was observed between postoperative T levels and preoperative marking rates in experimental subjects, despite the fact that most subjects failed to scent mark after bilateral LOT transections. The latter observation strengthens the inference that the bilateral deficits were independent of changes in basal hormone levels.

Animals↗