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Naunyn-Schmiedeberg's Archives of... Apr 1977Catecholamine release and cAMP accumulation were studied in bovine adrenal medulla slices in vitro. Acetylcholine (10(-4) M) and salbutamol (10(-6) M) caused increased...
Catecholamine release and cAMP accumulation were studied in bovine adrenal medulla slices in vitro. Acetylcholine (10(-4) M) and salbutamol (10(-6) M) caused increased release of catecholamines and accumulation of cAMP. Incubation in Ca2+ -free medium abolished the release of catecholamines and the increase of cAMP caused by acetylcholine but not that caused by salbutamol. In a membrane fraction of adrenal medulla acetylcholine (10(-4) M) had no effect on adenylate cyclase activity but salbutamol (10(-6) M) caused substantial activation of adenylate cyclase. It is suggested that acetylcholine has no direct effect on adenylate cyclase or cAMP in adrenal medulla and the accumulation of cAMP observed in slices incubated with acetylcholine is due to the effect of catecholamines, released by acetylcholine, on the medullary cells.
Topics: Acetylcholine; Adenylyl Cyclases; Adrenal Medulla; Albuterol; Animals; Calcium; Catecholamines; Cattle; Cyclic AMP; In Vitro Techniques
PubMed: 195228
DOI: 10.1007/BF00509267 -
Journal of UOEH Jun 2012The Ca2+ imaging method was developed to explore changes in excitability in adrenal medullary (AM) cells in a large field in response to synaptic input and chemicals....
The Ca2+ imaging method was developed to explore changes in excitability in adrenal medullary (AM) cells in a large field in response to synaptic input and chemicals. The adrenal medullae of rats and guinea pigs were retrogradely loaded with Ca2+ indicator through the adrenal vein. Nerve fibers remaining in the adrenal gland were electrically stimulated to induce postsynaptic responses in AM cells, and chemicals were applied to the cells by adding to the perfusate. With this method, gamma-aminobutyric acid (GABA) was shown to increase the Ca2+ signal in almost all and 40% AM cells in guinea pigs and rats, respectively.
Topics: Adrenal Medulla; Animals; Calcium; Electric Stimulation; Guinea Pigs; Male; Perfusion; Rats; Rats, Wistar; gamma-Aminobutyric Acid
PubMed: 22768423
DOI: 10.7888/juoeh.34.163 -
The Journal of Cell Biology Aug 1969Italico rats were injected with thymidine-(3)H 6 hr after the end of 300 hr of intermittent cold treatment. This plan of experiment ensured replacement in the adrenal...
Italico rats were injected with thymidine-(3)H 6 hr after the end of 300 hr of intermittent cold treatment. This plan of experiment ensured replacement in the adrenal medulla of lost DNA which is specifically sensitive to cold treatment and has a labeling index sufficiently high for statistical evaluation. The labeling index in the adrenal medulla decreases to one-half of the initial value within 10 days in animals subjected to further intermittent cold treatment and within 32 days in animals kept at room temperature. The very low mitotic index and the absence of doubling of the labeling index show that the observed labeling cannot be ascribed to pre-mitotic DNA synthesis. The concept of metabolic DNA adequately explains the findings.
Topics: Adaptation, Physiological; Adrenal Medulla; Animals; Cold Temperature; DNA; Mitosis; Periodicity; Rats; Time Factors; Tritium
PubMed: 5792334
DOI: 10.1083/jcb.42.2.460 -
The Journal of Pharmacology and... Aug 1962
Topics: Adrenal Medulla; Antihypertensive Agents; Guanethidine
PubMed: 13863089
DOI: No ID Found -
The American Journal of Anatomy May 1984The rat adrenal medulla architecture was examined using a combination of medullary blood vessel reconstructions and transmission electron microscopy. The peripheral...
The rat adrenal medulla architecture was examined using a combination of medullary blood vessel reconstructions and transmission electron microscopy. The peripheral radicles of the central vein and the medullary capillaries of the medullary arteries were thus precisely identified in the electron microscopic observations. The observations confirmed that the peripheral segments of the central vein were sinusoidal vessels with an attenuated and fenestrated endothelial wall. No ultrastructural differences were observed between segments lined by epinephrine-storing cells and those lined by norepinephrine-storing cells. The findings suggest that these peripheral segments of the adrenal central vein were sites of cortical hormonal effects on the adrenal medulla. The vessel structure does not support the hypothesis that medullary chromaffin-cell development is controlled by selective distribution of adrenal blood vessels.
Topics: Adrenal Medulla; Animals; Blood Vessels; Capillaries; Chromaffin System; Male; Microscopy, Electron; Rats; Rats, Inbred Strains; Veins
PubMed: 6731341
DOI: 10.1002/aja.1001700106 -
Brain Research Oct 1990In the present study, a significant increase in pain threshold (current to elicit vocalization to tail shock) was found 15 and 60 min after injection of dibutyryl cyclic...
In the present study, a significant increase in pain threshold (current to elicit vocalization to tail shock) was found 15 and 60 min after injection of dibutyryl cyclic AMP (db cAMP) (30 micrograms) into the lateral ventricle in rats bearing a transplant of fetal adrenal medulla (AM). By contrast, no effect on pain threshold was observed in rats bearing an AM transplant but receiving no db cAMP, or in rats receiving db cAMP but not bearing an AM transplant. In primary cultures of rat fetal chromaffin cells, db cAMP increased the number of neuron-like cells that showed both vasoactive intestinal polypeptide (VIP)- and tyrosine hydroxylase (TH)-like immunoreactivity. These findings indicate that db cAMP exerts a pharmacological modulation of the functional activity (i.e. elevation in pain thresholds) of fetal adrenal AM transplants, and induces phenotypic changes in cultured chromaffin cells with expression of a peptide that elevates pain threshold.
Topics: Adrenal Medulla; Analgesia; Animals; Bucladesine; Cells, Cultured; Cerebral Ventricles; Electroshock; Fetal Tissue Transplantation; Injections, Intraventricular; Male; Pain; Rats; Rats, Inbred Strains; Reference Values; Vocalization, Animal
PubMed: 1963102
DOI: 10.1016/0006-8993(90)90787-c -
British Journal of Pharmacology Feb 19761 The effects of chronic nicotine administration (1 or 10 mg/kg, s.c., twice daily) were studied in intact and denervated rat adrenal glands to determine the relative...
1 The effects of chronic nicotine administration (1 or 10 mg/kg, s.c., twice daily) were studied in intact and denervated rat adrenal glands to determine the relative roles of central input and direct actions on catecholamines. 2 Catecholamine depletion was obtained in the intact glands from 1-7 days of treatment with 10 mg/kg, with recovery by 14 days of treatment; catecholamines were not decreased in denervated adrenal glands. 3 Catecholamine depletion was accompanied by a decline in functional storage vesicles (determined by [3H]-adrenaline uptake per gland) in the intact side, while no change was seen in the denervated side; the proportion of newly synthesized vesicles increased markedly during 1-7 days of treatment with 10 mg/kg in the intact side, while a much smaller increase of shorter duration was seen in the denervated adrenal gland. 4 Chronic nicotine administration at either dose level induced tyrosine hydroxylase in both intact and denervated glands, but the increase occurred more slowly in the denervated glands. 5 Dopamine beta-hydroxylase levels increased similarly in both sides during treatment with nicotine (10 mg/kg). 6 These studies suggest that although long-term adrenal denervation eliminates the catecholamine depletion caused by chronic administration of nicotine, the mechanisms for induction of catecholamine synthesizing enzymes are still capable of responding to the drug.
Topics: Adrenal Medulla; Animals; Catecholamines; Chlorisondamine; Dopamine beta-Hydroxylase; Epinephrine; Iproniazid; Male; Nicotine; Rats; Tyrosine 3-Monooxygenase
PubMed: 3249
DOI: 10.1111/j.1476-5381.1976.tb07443.x -
Research Communications in Chemical... Jan 1981Intravenous administration of clonidine at a dose of 30 microgram/kg produced significant decrease both in spontaneous adrenal nerve activity and in adrenal...
Intravenous administration of clonidine at a dose of 30 microgram/kg produced significant decrease both in spontaneous adrenal nerve activity and in adrenal catecholamine secretion rate in rat. These findings could indicate that clonidine decreases catecholamine secretion from the adrenal medulla via the central nervous system.
Topics: Adrenal Medulla; Adrenergic Fibers; Animals; Blood Pressure; Catecholamines; Clonidine; Male; Rats
PubMed: 7255872
DOI: No ID Found -
Journal of Cardiovascular Pharmacology 1991The role of the sympathetic nervous system and adrenal medulla in the development of cardiovascular changes and hypertension was studied in spontaneously hypertensive... (Comparative Study)
Comparative Study
The role of the sympathetic nervous system and adrenal medulla in the development of cardiovascular changes and hypertension was studied in spontaneously hypertensive rats (SHRs), and the results compared with age-matched normotensive Wistar-Kyoto (WKY) rats. Sympathectomy was initiated in newborn rats through daily injection with antiserum to nerve growth factor for 1 week, followed by daily injection with guanethidine for 3 weeks. Removal of the adrenal medulla was carried out in 4-week-old rats after the last guanethidine injection. Such a combination treatment was effective in permanently preventing the development of hypertension in the SHRs, and the blood pressure was maintained at the level of WKY rats. The heart rate of the SHRs and WKY rats was not affected by such treatment. Hypertrophy of the heart and of the vessel wall in the mesenteric arteries was also prevented by such treatment. We conclude that in the SHR, the sympathetic nervous system and the adrenal medulla are essential for the development of cardiovascular changes and hypertension.
Topics: Adrenal Medulla; Animals; Hypertension; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Species Specificity; Sympathectomy; Sympathetic Nervous System
PubMed: 1715455
DOI: 10.1097/00005344-199117002-00025 -
Histology and Histopathology Jan 1998CRH occurs in the adrenal medulla of rats. We were interested to know whether CRH affects meduallary chromaffin cells in the absence of ACTH. We investigated the...
CRH occurs in the adrenal medulla of rats. We were interested to know whether CRH affects meduallary chromaffin cells in the absence of ACTH. We investigated the morphological changes of the adrenal medulla in Sprague Dawley rats with light and electron microscopy in normal rats, hypophysectomized rats, and hypophysectomized rats following injections of CRH (10 micrograms = 3 nmol for three days). Chromaffin cells were characterized by immunohistochemistry (anti-tyrosine hydroxylase). At light microscopy level chromaffin cells of hypophysectomized rats were reduced in number. On electron microscopy the number of granules and cell organelles were decreased. Following injections of CRH the medulla regained a more compact texture with cell organelles homogenously distributed, but with chromaffin granules still being reduced in number. Immunohistochemistry allowed the identification of chromaffin cells located within the adrenal cortex. In hypophysectomized rats these cells showed fewer signs of alterations compared to cells located within the medulla itself and had recovered better after treatment with CRH. In conclusion, CRH seems to exert a trophic effect on chromaffin cells in the absence of pituitary ACTH. This observation may provide further evidence for a close interaction of the two neuroendocrine stress systems.
Topics: Adrenal Medulla; Animals; Chromaffin Cells; Corticotropin-Releasing Hormone; Hypophysectomy; Male; Microscopy, Electron; Rats; Rats, Sprague-Dawley
PubMed: 9476637
DOI: 10.14670/HH-13.81