Search PubMed⌕ Search

Biomedical subjects

K E Moore

Publications and source records attributed to K E Moore.

At least 181 records · Page 10Linked to original sources
PubMed1981

Sexual differences in tuberoinfundibular dopamine nerve activity induced by neonatal androgen exposure.

The activities of different catecholaminergic neurons in the brains of male amd female rats were estimated by measuring (1) the rate of decline of dopamine (DA) and norepinephrine (NE) after inhibition of tyrosine hydroxylase with alpha-methyltyrosine (alpha-MT) and (2) the rate of accumulation of dihydroxyphenylalanine (DOPA) after inhibition of DOPA decarboxylase with NSD 1015 in brain regions containing the terminals of these neurons. In the median eminence the accumulation of DOPA and the alpha-MT-induced decline of DA, but not NE, were higher in the female than in the male, suggesting increased activity of tuberoinfundibular DA neurons in the female. There were no sexual differences in DA neurons which terminate in any of the other brain regions (striatum, olfactory tubercle, nucleus accumbens, posterior pituitary). To determine if the sexual difference in tuberoinfundibular DA neuronal activity results from neonatal exposure to androgens, the rate of DOPA accumulation was examined in the median eminence of females, males, and androgen-sterilized females (all of which were castrated as adults) and in adult males which were castrated as neonates. Similar values for DOPA accumulation were observed in the median eminence of castrate females and neonatally castrated males, while significantly lower values were observed in castrate males and androgen-sterilized females. Thus, neonatal exposure to androgens alters the activity of tuberoinfundibular DA neurons. Neonatal androgen-induced differences in tuberoinfundibular DA neuronal activity may be responsible, in part, for sexual differences in the hypothalamic regulation of hypophyseal hormone secretion.

Aging↗
PubMed1981

The incidence of water-related diseases in the Brak area, Libya from 1977 to 1979, before and after the installation of water treatment plants.

The incidence of nine water-related diseases in the Brak oases of the Sahara desert, before and after the installation of water treatment plants, are reported. Immediately following installation of the plants there was a drop in the incidence of most of the water related diseases. There then followed a gradual deterioration in the treatment plants and within a year the incidence of four of the diseases was again rising. Furthermore neither malaria or giardiases showed any drop in incidence over the study period. Bacillary dysentary, infectious hepatitis and bilharzia did however drop significantly over the three years. A correlation between bacillary dysentary and the mean noon-time temperature for two of the three years was noted.

Ascariasis↗
PubMed1980

Differential behavioral and biochemical effects of four dopaminergic agonists.

Some behavioral and biochemical effects of four dopaminergic agonists (apomorphine, piribedil, lergotrile, and bromocriptine) were determined in the mouse. As expected, all four drugs dose-dependently reversed the alpha-methyltyrosine-induced decline of forebrain dopamine. All four compounds reduced locomotor activity at low doses, but only apomorphine and bromocriptine increased motor activity at higher doses. All four drugs caused some reversal of the baclofen-induced elevation in forebrain dopamine concentrations, but only apomorphine and bromocriptine completely reversed the effects of baclofen. After chronic treatment with haloperidol, the behavioral effects of lergotrile and bromocriptine were altered. Doses of those drugs reducing motor activity in normal animals were ineffective after chronic haloperidol. The latent stimulation induced by bromocriptine was enhanced, while a stimulatory effect of lergotrile emerged in these animals. These effects were noted in conjunction with an enhanced sensitivity to the drug-induced decrease in dopamine turnover. These results demonstrate that dopamine agonists may be differentiated on the basis of certain behavioral and biochemical tests and suggest an interaction of these drugs with two different populations of dopamine receptors.

Animals↗
PubMed1980

Morphine differentially alters synthesis and turnover of dopamine in central neuronal systems.

On the basis of biochemical indices of dopamine (DA) nerve activity (decline of DA after inhibition of tyrosine hydroxylase, accumulation of DOPA after inhibition of DOPA decarboxylase) it was revealed that morphine increases the activity of nigrostriatal and mesolimbic DA nerves which terminate in the striatum, nucleus accumbens and olfactory tubercle, but reduce the activity of tuberoinfundibular DA nerves which terminate in the median eminence. Morphine had no effect on tuberohypophyseal DA nerves which project to the posterior pituitary. Naloxone was without effect per se, but blocked the effects of morphine on DOPA accumulation. Thus, morphine differentially alters the diverse DA neuronal systems in the rat brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

The effects of d-lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-methylamphetamine (DOM) and d-amphetamine on operant responding in control and 6-hydroxydopamine-treated rats.

The purpose of the present study was to determine the role of central catecholaminergic neuronal systems in the effects of LSD, DOM and d-amphetamine on fixed ratio (FR) operant responding in rats. Food-deprived male rats were trained to press a bar for food reinforcement on a FR-40 schedule. Control responding on this schedule is characterized by a rapid, constant rate of responding (approximately 100 responses/min) throughout a 40 min test session. LSD and DOM, as with other hallucinogens, produced dose-dependent periods of nonresponding or "pausing," followed by reinstatement of responding at or near the control rate. Administration of the non-hallucinogen, d-amphetamine, did not produce "pausing," but caused the response rate to slow and become erratic. In animals pretreated intraventricularly with 6-hydroxydopamine (6-OHDA; 200 micrograms/10 microliter X 2), the response to LSD and DOM was unchanged, while the response to d-amphetamine was significantly diminished. The neurotoxin significantly decreased brain catecholamines to less than 25 percent of control in al regions examined, without altering 5-HT concentrations in these same regions. These data demonstrate that the effects of LSD and DOM on FR-40 responding are quite different from those of d-amphetamine, and that this difference may be due to the extent of catecholamine involvement in the effects of these agents.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1980

Naloxone potentiates the disruptive effects of mescaline on operant responding in the rat.

Food-deprived male rats were trained to press a lever on a fixed ratio-40 (FR-40) operant schedule for food reinforcement. Administration of mescaline (4.0--10.0 mg/kg) immediately before the start of the operant session resulted in a cessation of responding for some portion of the 40-min period ("hallucinatory pause"). The duration of this pause was found to be dose-dependent. Although administration of naloxone alone (1.0-8.0 mg/kg, five minutes prior to the start of the session) had no effect on FR-40 responding per se, pretreatment with this agent significantly potentiated the disruptive effects of mescaline. This potentiation by naloxone was further shown to be dose-dependent. These data suggest that the effects of the phenethylamine hallucinogen mescaline are potentiated by pretreatment with the narcotic antagonist naloxone.

Animals↗
PubMed1980

Enhancement of the behavioral effects of 2,5-dimethoxy-4-methyl-amphetamine (DOM) by pretreatment with p-chlorophenylalanine.

Seven food deprived male rats were trained to press a bar on a fixed ratio-40 (FR-40) schedule of food reinforcement. Administration of 0.5 mg/kg 2,5-dimethoxy-4-methyl amphetamine (DOM) immediately before the start of the session resulted in cessation of responding for some portion of the 40-min test session. Three successive days of p-chlorophenylalanine (PCPA) administration (100 mg/kg) 30 min after each session reduced 5-hydroxytryptamine (5-HT) to 15-26% of control concentrations in various brain regions but did not alter control rates of responding under the FR-40 schedule. Administration of 0.5 mg/kg DOM following this PCPA pretreatment resulted in a greater amount of nonresponding than observed earlier. These data suggest that the effects of the phenethylamine hallucinogen DOM are enhanced by disruption of 5-HT neuronal activity.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1980

Increased self-administration of d-amphetamine after destruction of 5-hydroxytryptaminergic neurons.

Rats will initiate self-administration of d-amphetamine and achieve a stable injection rate within 7-10 days. Animals injected intraventricularly with 5,7-dihydroxytryptamine, which selectively destroys 5-hydroxytryptamine-containing neurons, consistently self-injected larger amounts of d-amphetamine from the first day of training, but the acquisition of a stable rate of drug self-administration was not altered. Bilateral microinjection of 5,7-dihydroxytryptamine into nucleus accumbens failed to alter either the acquisition of d-amphetamine self-administration or the maintenance of a stable rate of injection.

5,7-Dihydroxytryptamine↗
PubMed1980

Dehydration selectively increases dopamine synthesis in tuberohypophyseal dopaminergic neurons.

The concentration of dopamine (DA) and the accumulation of DOPA following the administration of a decarboxylase inhibitor were determined in the rat striatum, median eminence and posterior pituitary, regions containing terminals of nigrostriatal, tuberoinfundibular and tuberohypophyseal DA nerves, respectively. Severe dehydration (2 days water deprivation followed by 3 days of 2% NaCl substituted for drinking water) increased the concentration of DA in the posterior pituitary but not in the striatum or median eminence. Less severe dehydration caused by 2 or 3 days of water deprivation did not alter steady state concentrations of DA, but increased DOPA accumulation, an index of DA nerve activity, only in the posterior pituitary. Food deprivation for 3 days did not alter DOPA accumulation in the posterior pituitary. These results suggest that dehydration selectively activates the tuberohypophyseal DA neuronal system in the rat.

Animals↗