Effect of dexamethasone implanted in different brain areas on the morphine-induced PRL, GH and ACTH/corticosterone secretion. 1991

D T Kiem, and L Bartha, and G B Makara
Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.

We studied the effect of dexamethasone (DEX) implantation in male Wistar rats to elucidate the site of action of morphine-induced prolactin (PRL), growth hormone (GH), adrenocorticotropic hormone (ACTH) and corticosterone (B) secretion. DEX or cholesterol was implanted in the close vicinity of the paraventricular (PVN), or the arcuate nuclei (ARN) of the hypothalamus or into the hippocampus. Five days after implantation blood samples were taken 30 min after i.p. morphine by decapitation or through an indwelling cannula 15, 30, 60 min after i.v. injection. DEX implanted near the PVN resulted in a blockade of morphine-induced ACTH and B secretion. In contrast, GH response to morphine was enhanced, while that of PRL was unchanged. DEX implanted near the ARN significantly inhibited the PRL-releasing effect of morphine, but was without any influence on the PRL secretion induced by haloperidol. There was a partial reduction in the B response to morphine, and GH secretion was unchanged. Dorsal hippocampal implants were without any effect on the morphine-induced GH, PRL or B secretion. We suggest that the site of glucocorticoid inhibitory action in the hypothalamus is the PVN for the opiate-induced ACTH/B secretion, and the ARN for the morphine-induced PRL release. The enhanced GH response to morphine observed in DEX-PVN implanted rats might be due to a decreased somatostatin tone.

UI MeSH Term Description Entries
D008297 Male Males
D009020 Morphine The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle. Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D010286 Paraventricular Hypothalamic Nucleus Nucleus in the anterior part of the HYPOTHALAMUS. Hypothalamic Paraventricular Nucleus,Paraventricular Nucleus,Hypothalamic Nucleus, Paraventricular,Nucleus, Hypothalamic Paraventricular,Nucleus, Paraventricular,Nucleus, Paraventricular Hypothalamic,Paraventricular Nucleus, Hypothalamic
D010907 Pituitary Hormones Hormones secreted by the PITUITARY GLAND including those from the anterior lobe (adenohypophysis), the posterior lobe (neurohypophysis), and the ill-defined intermediate lobe. Structurally, they include small peptides, proteins, and glycoproteins. They are under the regulation of neural signals (NEUROTRANSMITTERS) or neuroendocrine signals (HYPOTHALAMIC HORMONES) from the hypothalamus as well as feedback from their targets such as ADRENAL CORTEX HORMONES; ANDROGENS; ESTROGENS. Hormones, Pituitary
D011388 Prolactin A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate. Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D001921 Brain The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM. Encephalon
D001923 Brain Chemistry Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states. Chemistry, Brain,Brain Chemistries,Chemistries, Brain
D003345 Corticosterone An adrenocortical steroid that has modest but significant activities as a mineralocorticoid and a glucocorticoid. (From Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p1437)
D003907 Dexamethasone An anti-inflammatory 9-fluoro-glucocorticoid. Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.

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