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Biomedical subjects

J A Peters

Publications and source records attributed to J A Peters.

At least 109 records · Page 6Linked to original sources
PubMed1976

Influence of cholinergic receptor blockade on drug-induced prolactin release in the monkey.

The influence of varying doses of perphenazine, thyrotropin-releasing hormone (TRH) and serotonin on prolactin release was examined in two species of monkeys: rhesus (Macaca mulatta) and crab-eating (Macaca fascicularis). The intravenous administration of 0.33 mg/kg body weight of perphenazine or 1.0 mug/kg body weight of TRH gave a greater release of prolactin than higher doses of perphenazine (1.0 mg/kg) or TRH) (3.4 mug/kg), respectively. Prolactin release induced by serotonin at doses of 1, 5 and 10 mug/kg was similar. Both atropine sulfate (Atr-SO4) and atropine methyl nitrate (Atr-MN) at a similar base level potentiated the prolactin releasing action of the high dose of perphenazine suggesting that high doses of perphenazine activate a cholinergic inhibitory component present in the pituitary. Atropine sulfate had no potentiating action on the TRH-induced prolactin release, while Atr-MN appeared to prolong the response of TRH without potentiating it. Neither form of atropine had any influence on serotonin-induced prolactin release. The data indicated that the lower prolactin response to high doses of perphenazine and TRH were brought about by different mechanisms, and that the mechanism for perphenazine appeared to be mediated through a pituitary cholinergic system.

Animals↗
PubMed1976

Submucous lipoma of the stomach: a case report.

A 54-year-old woman presented with a 4-day history of melena and a 1-day history of hematemesis. Radiographs were suggestive of a malignant gastric polyp. Gastrotomy revealed a polyp projecting from the anterior wall of the stomach. The polyp was exised and the patient has since been well. Although rare, gastric lipomas are important because they may cause hemorrhage, abdominal pain, syspepsia and pyloric obstruction; moreover, they are amenable to surgical treatment.

Female↗
PubMed1975

Induction of pseudopregnancy in the rat by electrochemical stimulation of the brain.

Electrochemical stimulation of the neocortex, VMH-arcuate hypothalamus, medial preoptic area, corticomedial amygdala, and dorsal hippocampus was performed under pentobarbital anesthesia to determine the brain regions involved in prolactin release as evidenced by pseudopregnancy. Stimulation occurred on the day of vaginal estrus, followed 4 days later by uterine traumatization. All animals were sacrificed 8 days after brain stimulation. Medial preoptic sitmulation resulted in an 83% incidence of pseudopregnancy while VMH-arcuate stimulation resulted in 43% incidence. Amygdaloid and hippocampal stimulation resulted in a lower incidence of pseudopregnancy (20 and 24%, respectively). Stimulation of the neocortex or sham stimulation of the five brain regions did not induce pseudopregnancy. These data indicate that the MPOA and VMH-arcuate hypothalamus are areas which may facilitate the release of prolactin necessary for the development of pseudopregnancy. The lower incidence of deciduomata formation resulting from electrochemical stimulation on the amygdala and hippocampus suggest that these areas have a minor effect on stimulating the induction of pseudopregnancy.

Amygdala↗
PubMed1975

Blockage of induced pseudopregnancy by electrochemical stimulation of the limbic system.

Pseudopregnancy induced by cervical stimulation was inhibited by acute electrochemical stimulation of the corticomedial amygdala or dorsal hippocampus under sodium pentobarbital anesthesia (40 mg/kg) in adult, cyclic female Sprague-Dawley rats. The degree to which pseudopregnancy was blocked depended on temporal conditions of brain stimulation and sodium pentobarbital administration. Pentobarbital alone had a suppressing effect on the incidence of pseudopregnancy, especially when it preceded cervical stimulation. Limbic stimulation before cervical stimulation had a tendency to potentiate the suppression of pseudopregnancy by pentobarbital. After cervical stimulation, hippocampal stimulation tended to inhibit the development of pseudopregnancy, potentiating the pentobarbital suppression, while amygdala stimulation tended to override the pentobarbital blockage of pseudopregnancy. These findings suggest a negative influence of these two limbic structures and pentobarbital on the secretion of prolactin.

Amygdala↗