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Biomedical subjects

D M Stoff

Publications and source records attributed to D M Stoff.

At least 37 records · Page 2Linked to original sources
PubMed1983

Effects of combined administration of imipramine and chlorpromazine on beta- and alpha 2-adrenergic receptors in rat cerebral cortex.

Administration of the combination of antidepressant and neuroleptic drugs has been reported to have a synergistic effect in the treatment of delusional depression. The effects of chronic coadministration of imipramine (IMIP) and chlorpromazine (CPZ) on beta-adrenergic and alpha 2-adrenergic binding sites in rat cerebral cortex were studied. The combination caused the same reduction in the number of beta-adrenergic receptors as IMIP alone. No changes in alpha 2-adrenergic receptors were observed with IMIP and/or CPZ.

Animals↗
PubMed1983

The time and space machine: continuous measurement of drug-induced behavior patterns in the rat.

Because of the increasing demand for refined techniques to record drug-induced motoric changes, we designed and evaluated a computer monitoring system with continuous measurement of different parameters of rat motor activity. This system is particularly useful for chronic drug studies because it can characterize patterns of behavior and combines the residential and experimental environments, thus enabling automated behavioral measurement without experimenter intervention. Behavioral responses are detected by a capacitance-sensing device that generates bipolar analog voltages representing the location of the rat in its home cage. These voltages are first transduced, then amplified, and finally converted to digital signals in a computer that processes the input using algorithms to define specific responses. The technique pinpoints the exact location of the rat and identifies many kinds of responses simultaneously (e.g., rearing, circling) by tracking the path of movement or setting threshold limits. Some threshold values (representing rearing, gross movements, fine movements) were validated against stereotypy rating scales for amphetamine, apomorphine, and beta-phenylethylamine. Among these drugs, quantitatively distinct response profiles were obtained. The system has wide applications for studies of biological rhythms, sleep, aging, and drug toxicology.

Animals↗
PubMed1983

Interstrain comparison of avoidance behavior and neurochemical parameters of brain cholinergic function.

Five rat strains (Long-Evans Hooded, Zivic Miller, Lewis, Buffalo and Fischer-344) were tested in a shuttlebox conditioned avoidance task and the differences in the performance levels among the strains were noted. In parallel experiments using naive rats, the acetylcholine concentrations in eight brain regions and the acetylcholine turnover rate in five brain regions were determined for these strains. Interstrain differences in these parameters were found but no correlation between avoidance performance and either of these measures was apparent in any brain region studied. In separate experiments, no differences were found in the hippocampal acetylcholine concentration or the turnover rate among good performing Hooded, poor performing Hooded or untested Hooded rats. Similarly, no differences in regional acetylcholine turnover rates were found between naive rats of the Iowa Reactive and Nonreactive strains. [3H]-QNB (quinuclidinyl benzilate) binding was studied in three brain regions in the five strains, but no large interstrain differences in binding characteristics were found. In contrast to interpretations of other workers based on less direct assay methods involving fewer strains, we conclude that no strong correlation exists between avoidance performance ability and basal levels of brain cholinergic activity.

Acetylcholine↗
PubMed1981

beta-Phenylethylamine reversal of chlorpromazine-induced activation of striatal tyrosine hydroxylase and catalepsy.

The ability of beta-phenylethylamine (PEA) to reverse (1) chlorpromazine-induced activation of striatal tyrosine hydroxylase, and (2) catalepsy produced by chlorpromazine, was examined. PEA, in a dose of 75 mg/kg, caused approximately 50% reduction in the degree of tyrosine hydroxylase stimulation produced by 20 mg/kg chlorpromazine. After 150 mg/kg PEA, complete reversal of tyrosine hydroxylase activation and partial reversal of catalepsy was observed. In these experiments, PEA was found to be about 10 times less potent than amphetamine and 25 times less potent than apomorphine. Thus, the ability of PEA to reverse the neurochemical and behavioral effects of striatal dopamine blockade is similar to known dopamine agonists.

Animals↗
PubMed1978

Testosterone-attenuated stereotype and hyperactivity induced by beta-phenylethylamine in pargyline-pretreated rats.

Testosterone pretreatment (1.0-4.0 mg/kg) attenuated, in a dose-response fashion, the induction of stereotyped behavior and hyperactivity by pargyline (0.25, 4.0 mg/kg) and beta-phenylethylamine (8.0, 16.0 mg/kg) in preubertal, male rats. The dyskinetic movements induced by pargyline and beta-phenylethylamine were proposed as a possible animal model for tardive dyskinesias. Attenuation by testosterone of these effects suggested an hormonal involvement consistent with the reported predominant occurrence of tardive dyskinesias in women and in the elderly.

Animals↗
PubMed1977

Dose response and time course effects of N,N-dimethyltryptamine on disruption of rat shuttlebox avoidance.

N,N-Dimethyltryptamine (DMT) was given (ip) in different doses (0.25, 0.5, 1.0, 2.0, 4.0, 8.0 mg/kg) in a randomized order to a group of ten rats (Fisher 344/Mai) who were trained to a high, stable base line of conditioned avoidance responding in the shuttlebox. DMT produced dose-dependent disruptive effects, as a sigmoid function, with 1.0 mg/kg the minimal dose causing disruption and progressively more disruption with increasing doses, reaching a plateau at the highest dose. The disruptive effects were time-related, with onset and peak 8 min after injection, gradual decline thereafter, and disappearance by about 25-30 min. Both the threshold dose and time course for the disruptive effects correspond closely to what has been previously reported for DMT's psychological effects in humans.

Animals↗
PubMed1976

Parachlorophenylalanine potentiates facilitatory effects of mescaline on shuttlebox escape/avoidance in rats.

Acute parachlorophenylalanine (pCPA) pretreatment (150 mg/kg, i.p., 24 h beforehand) potentiated facilitatory effects of mescaline (39.6 mg/kg i.p.) on shuttlebox escape/avoidance in hooded rats, tested in two different situations: 1. during aquisition of avoidance behavior (Experiment 1); and 2. in stable pretrained poor avoiders (Experiment 2). pCPA alone did not influence avoidance behavior in either situation. Mescaline, with pCPA pretreatment, may be associated with long-term behavioral effects; all rats treated with this combination were later found to be poor avoiders, unable to achieve a stable baseline of good avoidance. pCPA significantly depleted brain norepinephrine and dopamine, as well as serotonin, measured after testing in the second situation.

Animals↗
PubMed1976

Dose-response effects of beta-phenylethylamine on stereotyped behavior in pargyline-pretreated rats.

We studied the dose-response and the time-course effect of beta-phenylethylamine (4.0-64.0 mg/kg, ip) on stereotyped behavior and motor activity in male Sprague-Dawley rats pretreated 2 hr eariler with pargyline (0.25-8.0 mg/kg, iv). Stereotyped behavior, defined as repetitive, nongoal-directed head movements and sniffing, and changes in motor activity were observed immediately after injection of beta-phenylethylamine for a 1 hr period. With increasing doses of pargyline pretreatment, beta-phenylethylamine produced, in a dose-response relationship, progressively more stereotyped behavior accompanied by increased motor activity. Without pargyline pretreatment, only 64.0 mg/kg beta-phenylethylamine induced behavioral changes. Stereotyped behavior and increased motor activity had an onset at 4-6 min after the injection of beta-phenylethylamine, peak at 10-30 min, and gradual decline in the next 10-20 min. These results are discussed in terms of a possible relationship with the degree of inhibition of Type a and Type B monoamine oxidase acused by the different doses of pargyline.

Animals↗