Biomedical subjects
Publications and source records attributed to N P Plotnikoff.
Thyrotropin releasing hormone potentiates the behaviorial effects of dopa plus pargyline in mice. Because the potentiation occurs in hypophysectomized mice, as well as in normal mice, the phenomenon is independent of the release of thyroid stimulating hormone from the pituitary. Possible mechanisms and clinical implications are discussed.
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The present study in mice demonstrated the TRH when administered over 5 days remained active in the Everett Dopamine Potentiation Test. No evidence of tolerance was observed. In fact, an accumulative effect of TRH appeared to take place. Ablation of the adrenals, ovaries, testes, pineal, spleen, parathyroid, one kidney, or thymus did disrupt this behavioral potentiation of dopamine by TRH. TRH was found to potentiate the effects of imipramine. T3, T4, and TSH were found to be active in the DOPA potentiating test. No overt toxicity was observed between TRH and pargyline or between TRH and DOPA. Toxicity was seen only when all three agents were used together. TRH was found active in young and old mice. TRH was also found active in potentiating the central effects of serotonin. Biogenic amine brain levels in mice were not altered by TRH when administered for five days. Alpha-methyl-p-tyrosine reduced the activity of TRH in the dopamine potentiation test, suggesting dopaminergic mechanisms are involved by a direct receptor interaction.
A review of the literature in the field of psychoneuroimmunology was reported by Robert Ader [1]. Basically, three research approaches have been used to demonstrate a relationship between central sites within the brain that have modulatory influences on the immune system. These include: (1) both the electrical stimulation and surgical lesioning of nuclei in the hypothalamus; (2) traditional behavioral conditioning; and (3) behavioral stress studies. The mechanisms of action for the psychoneuroimmunologic response appear to be focused in three areas: (1) the autonomic nervous system, where direct anatomical connections from the brain to the immune system have been recently demonstrated; (2) the endocrine system where the individual hormones have direct and indirect effects on the immune system; and (3) enkephalins-endorphins in the brain, pituitary, and adrenals that also have direct and indirect effects on the immune system. Examples of drug effects on the above complex systems will be centered on morphine and the enkephalins-endorphins with reference to drugs of abuse, food additives, and cosmetics.