PubMed Health⌕ Search

Biomedical subjects

A L Gascon

Publications and source records attributed to A L Gascon.

At least 19 recordsLinked to original sources
PubMed1982

Relationship between plasma corticosterone and adrenal epinephrine after diazepam treatment in rats.

Following recent observations that diazepam treatment increases adrenal epinephrine in rats, we were interested in studying the possible mechanisms of this action of diazepam on rat adrenal glands. All diazepam treatments studied (1-25 mg . kg-1.day-1 for 10 days) led to an increase in adrenal epinephrine following a linear dose-effect relationship. Since epinephrine synthesis is under neuronal and humoral controls, we investigated their respective importance in the effect of diazepam on the adrenal gland. The denervation of the adrenal gland did not prevent the increase in adrenal epinephrine by diazepam treatment. On the hand, diazepam treatment was shown to cause an increase in plasma corticosterone in parallel with an increase in adrenal epinephrine. Administration of dexamethasone (a synthetic corticoid) and hypophysectomy prevented the increase in adrenal epinephrine and plasma corticosterone resulting from diazepam treatment. We thus conclude that the increase in adrenal epinephrine seen after diazepam treatment is parallel to the increase in plasma corticosterone. Moreover, since the action of diazepam on adrenal epinephrine is prevented by dexamethasone or hypophysectomy, we hypothesize that diazepam is acting on the adrenal cortex via the release of adrenocorticotropic hormone (ACTH). ACTH and corticosterone would be responsible for the increased activity of epinephrine-synthesizing enzymes in adrenal medulla.

Adrenal Glands↗
PubMed1978

Relationship between analgesia and turnover of brain biogenic amines.

The analgesic activity of morphine, delta9THC, and sodium salicylate was studied concomitantly with changes in brainstem and cortex turnover of dopamine (DA), noradrenaline (NA), and serotonin (5HT). The results show that a correlation exists between the presence of analgesia and the increased turnover rates of the three biogenic amines. Morphine and sodium salicylate induced analgesia is accompanied by an increased turnover rate of all three biogenic amines; delta9THC-induced analgesia is accompanied by an increased turnover rate of DA and 5HT only. There is, however, no consistent relationship between the degree of analgesia and the degree of change in the turnover rates. The existence of the endogenous morphine-like substances, endorphines, may explain why morphine analgesia is distinct from that of delta9THC and sodium salicylate. The possible relationship between this morphine-like substance and biogenic amines is discussed.

Analgesia↗
PubMed1977

Effect of acute stress and ouabain administration on adrenal catecholamine content and cardiac function of rats pretreated with diazepam.

The experiments described were carried out in an attempt to determine the participation of adrenal catecholamines in the higher incidence of cardiac arrhythmias produced by acute stress or ouabain injections in diazepam-treated animals. The pretreatments of rats with diazepam (150 mg kg-1 d-1) increase significantly the adrenal catecholamine content. Consequently, the application of electrical and immobilization stress releases more catecholamines from the adrenal glands of the diazepam-treated rats and also produces higher incidence of ventricular extrasystoles. Furthermore, various pretreatments of rats with diazepam (5-150 mg kg-1 d-1) also lead to an increase in the catecholamine content of the adrenal gland. In diazepam-treated rats, the intravenous administration of ouabain produces a greater release of adrenal catecholamines as well as a greater incidence of cardiac arrhythmias. Several hypotheses are proposed to explain the elevation of adrenal catecholamines and also the higher incidence of ventricular arrhythmias.

Adrenal Glands↗
PubMed1975

Increase in catecholamine content of the rat adrenals after pretreatment with diazepam.

The effect of subacute pretreatment with diazepam was studied on the catecholamine content of the heart and adrenals of the rat. The results show that at all doses studied, subacute treatment with diazepam increases the catecholamine content of the adrenal glands and there is no change in the noradrenaline content of the heart and brain.

Adrenal Glands↗
PubMed1975

Influence of phenobarbital pretreatment on tissue catecholamine content of various animal species.

The influence of phenobarbital pretreatment on tissue catecholamine content was studied in various animal species. The results reported in this communication whow that such pretreatment increases the catecholamine content of the adrenal and the male accessory sexual tissues of the guinea-pig and the rabbit, while with the rat and hamster, only the adrenaline content of the adrenals was increased. In the female guinea-pig, there was an increase in the catecholamine content of the adrenals and the female accessory sexual tissues. It was concluded that the difference observed among species may be related either to the different type of adrenergic innervation or to a different influence of the adrenal gland on the sexual accessory tissues.

Adrenal Glands↗
PubMed1975

An attempt to correlated analgesia to changes in brain neuromediators in rats.

The analgesic activity of delta9THC, morphine and sodium salicylate was studied concomitantly with changes in brain stem levels of 5HT, 5HIAA, DA and NA. The results show that a correlation exists between analgesia and changes in the serotonergic system of the brain stem. Furthermore morphine sulfate was found to increase the DA concentration of the brain stem while delta9THC increased NA levels. We conclude that serotonergic system may be of major importance in analgesia while simultaneous changes in this system and/or the DA and NA systems may lead to a more pronounced analgesic activity.

Analgesia↗
PubMed1969

Influence of rat plasma and of various cations on the anti-eledoisin activity of morin.

1. The musculotropic activity of eledosin on the isolated guinea-pig ileum is antagonized by morin, a flavonoid derivative.2. The anti-eledoisin activity of morin is abolished by fresh rat plasma and by deproteinized rat plasma, but not by deionized plasma.3. Cupric acetate can restore the inhibitory property of the deionized plasma and can also inactivate morin.4. This effect of rat plasma and of cupric acetate is inhibited by (-)-penicill-amine and by N-acetyl-(+/-)-penicillamine.5. It is concluded that, when in contact with rat plasma, morin is probably inactivated as a consequence of the formation of a complex with the plasma copper.

Acetates↗