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Biomedical subjects

R J Hitzemann

Publications and source records attributed to R J Hitzemann.

At least 73 records · Page 4Linked to original sources
PubMed1977

Effects of withdrawal from chronic amphetamine intoxication on exploratory and stereotyped behaviors in the rat.

Rats were administered 3, 6, and 12 mg/kg of d-amphetamine s.c. twice daily on a weekly increasing staircase schedule. On days 1, 7, 14, and 28 after the last injection of amphetamine the animals were challenged with 1 and 3 mg/kg of d-amphetamine and their behavior was observed. The 7-, 14-, and 28-day withdrawn animals required less amphetamine than controls to induce stereotyped behaviors. However, it was found that withdrawn animals and control animals were equally sensitive to the effects of apomorphine. Reserpine pretreatment eliminated the differences between control and withdrawn animals. alpha-Methyl tyrosine pretreatment blocked the effects of 1 but not 3 mg/kg of d-amphetamine in the withdrawn animals. Possible chemical mechanisms underlying the change in amphetamine sensitivity in the withdrawn animals are discussed.

Animals↗
PubMed1977

Influence of morphine on protein synthesis in synaptic plasma membranes of the rat brain.

The effects of acute and chronic morphine treatment on the incorporation of 3H-lysine into synaptic proteins were studied. No changes related to tolerance development were observed in the total incorporation of 3H-lysine into cortical or subcortical synaptic plasma membrane (SPM) or synaptic soluble proteins. Two populations of subcortical SPM were prepared, one from light (L) and one from heavy (H) nerve ending particles. When the labeled SPM-L proteins were separated by means of sodium dodecyl sulfate disc gel electrophoresis, an increased amount of label was found in the high molecular weight region of the gel. This increase depended on the rate of tolerance development. In contrast to the results found in the SPM-L gels, chronic morphinization significantly decreased the amount of high molecular weight labeled protein recovered from SPM-H gels.

Animals↗
PubMed1976

On the possible role of brain protein synthesis in functional barbiturate tolerance.

Pentobarbital pellet implantation increased more than 200% the ED50 dose of pentobarbital required to induce loss of the righting reflex within 2 min of i.p. injection and increased the onset of barbital-induced sleep. Both tests of functional barbiturate tolerance were blocked by the intraventricular injection of cycloheximide. The effects of acute (45 mg/kg i.p.) and chronic (pellet implantation) pentobarbital treatment on the incorporation of 3/-lysine into the protein of various subcellular fractions of the cortex and subcortex were studied. In the subcortex, chronic pentobarbital treatment significantly stimulated protein synthesis 40-50% in the microsomal, soluble and mitochondrial fractions. Both acute and chronic pentobarbital treatments significantly increased (3H-lys)-protein accumulation in a fraction of synaptic plasma membranes derived from a population of nerve ending particles (NEP) enriched in gamma-aminobutyric acid (GABA). The possible significance of these data to pentobarbital tolerance and dependence development is discussed.

Animals↗
PubMed1976

Influence of morphine on protein synthesis in discrete subcellular fractions of the rat brain.

Extensive time course (15 min to 24 hr) measurements were made of the effects of acute and chronic morphine treatment on the incorporation of 3H-lysine into rat brain proteins. Acute and chronic morphine treatment inhibited cortical protein synthesis in the microsomal (Mc), mitochondrial (Mw) and soluble fractions (Sol.). In the subcortex, acute morphine stimulated labelled protein accumulation in the Mc and Mw fractions, Chronic morphine treatment decreased 3H-lys-protein accumulation in these fractions.

Animals↗