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Biomedical subjects

F Drago

Publications and source records attributed to F Drago.

At least 199 records · Page 11Linked to original sources
PubMed1984

Effects of hyperprolactinaemia on core temperature of the rat.

The effects of endogenous hyperprolactinaemia (HPRL), as induced by pituitary homografts under the kidney capsule, on core temperature (Tc) was investigated in rats before and after the application of restraint stress. HPRL was accompanied by a significant decrease in Tc of freely moving rats, as observed for four days after pituitary homografts. HPRL-induced hypothermia was totally reversed by intraperitoneal (IP) injection of naloxone. In normoprolactinaemic (NPRL) rats, IP administration of naloxone caused a small but significant decrease in Tc and attenuated rise in temperature following the application of restraint stress. After application of restraint stress, Tc of HPRL rats raised to the level of unstressed NPRL rats. However, HRPL rats injected IP with naloxone showed no increase in Tc after restraint stress application. The effects of HPRL on Tc seem to involve an opioid component, and support the concept of a role played by stress hormones of hypophyseal origin in the control of Tc.

Animals↗
PubMed1984

Behavioral effects of arginine in male rats.

The effects of aminoacid arginine on conditioned and unconditioned behavior were studied in male rats. Arginine was administered orally at different dose levels. Both acute and subchronic (7 days) treatment schedule was performed. Exploratory behavior of the rats was studied in an open field. Acquisition of active avoidance behavior was studied in the shuttle-box test situation, and retention of passive avoidance reaction was studied in a step-through type of passive avoidance behavior. Acute administration of arginine failed to affect the acquisition and the retention of avoidance responses, and exploratory behavior of the rats. A 7-day treatment with the aminoacid caused an increase in ambulation of rats of Wistar strain, and a facilitation of acquisition and retention of avoidance responses in rats of CDR strain with poor learning capacity. It is possible that behavioral effects or arginine depend on its involvement in nucleic acid synthesis.

Animals↗
PubMed1984

Effects of valproic acid derivatives on the acquisition of active avoidance behavior in the rat.

The effects of valproic acid derivatives on the acquisition of active avoidance behavior have been studied in the rat. Sodium valproate (50 and 100 mg/kg), magnesium valproate (100 mg/kg) and dipropylacetamide (100 mg/kg) were administered intraperitoneally 1 hr prior to the behavioral test (shuttle-box, single session). Acquisition of active avoidance behavior was facilitated by sodium valproate, unaffected by magnesium valproate, and inhibited by dipropylacetamide. These findings suggest that behavioral effects of valproic acid derivatives cannot be explained only in terms of a general inhibitory action on the central nervous system.

Animals↗
PubMed1983

Naltrexone-sensitive behavioral actions of the ACTH 4-9 analog (Org 2766).

The effects of the ACTH 4-9 analog (Org 2766) and the COOH-terminal tripeptide of Org 2766 (Phe-D-Lys-Phe; PDLP) on retrieval of one-trial learning passive avoidance behavior were compared with those of beta-endorphin, [Met5]-enkephalin, [D-Ala2,Met5]-enkephalin, des-Tyr1-[Met5]-enkephalin and des-enkephalin-gamma-endorphin (DE gamma E). Amounts of intracerebroventricularly administered Org 2766, PDLP, [Met5]-enkephalin, [D-Ala2,Met5]-enkephalin and DE gamma E, which induced a comparable attenuation of passive avoidance behavior were determined. Pretreatment with the opiate antagonist naltrexone prevented the attenuating effect of these peptides on passive avoidance behavior except that of DE gamma E. The attenuating effect of Org 2766 and of [Met5]-enkephalin was reversed to facilitation of passive avoidance behavior in the presence of naltrexone. Subcutaneous treatment with Org 2766 and [D-Phe7]-ACTH 4-10 decreased electrical self-stimulation behavior elicited from the medial septal area. Naltrexone prevented the inhibitory effect of Org 2766 on this behavior, but not that of [D-Phe7]-ACTH 4-10. Although the attenuating effect of PDLP on passive avoidance behavior was not reduced by pretreatment with [Met5]-enkephalin- or beta-endorphin-antiserum, and PDLP induced neither analgesia nor excessive grooming, the data suggest that the inhibitory effect of Org 2766 and PDLP on passive avoidance behavior and electrical self-stimulation are mediated by endorphin systems in the brain.

Adrenocorticotropic Hormone↗
PubMed1983

Prolactin-enhanced grooming behavior: interaction with ACTH.

The interaction between prolactin (PRL) and ACTH in enhancing grooming behavior after intracerebroventricular (i.c.v.) administration was investigated in intact and endogenously hyperprolactinaemic rats. In intact rats, 4 h after the i.c.v. injection of rat PRL or ACTH, a subsequent administration of ACTH or rat PRL did induce similar excessive grooming as observed after the first injections. In hyperprolactinaemic rats, which displayed excessive grooming 12 days after homografting adenopituitaries under the kidney capsule, i.c.v. injection of rat PRL failed to enhance further the grooming activity while this behavior was substantially enhanced by i.c.v. injection of ACTH1-24. Twenty-six days after surgery, when the grooming activity of hyperprolactinaemic rats was at the same level as control animals, the i.c.v. injection of rat PRL was effective in inducing excessive grooming in control but not in hyperprolactinaemic animals. In contrast, at this time the i.c.v. injection of ACTH1-24 induced again excessive grooming in both hyperprolactinaemic and control rats. Accordingly, there was no cross-tolerance between PRL and ACTH in inducing excessive grooming, but hyperprolactinaemic rats became hyposensitive to exogenous PRL. It is suggested that although PRL and ACTH may affect common neurotransmitter systems in the brain, the two hormones probably act on independent neural mechanisms in inducing excessive grooming in the rat.

Adrenocorticotropic Hormone↗
PubMed1983

Pituitary stalk section transiently impairs the acquisition of shuttle box avoidance behavior.

Three days after stalk section, rats displayed a marked deficit in acquiring a shuttle box avoidance response. The performance of stalk sectioned rats was similar to that of 3-day hypophysectomized rats. At eighteen days after stalk section acquisition of the avoidance response was, however, not different from that of sham-operated controls. Stalk sectioned rats that showed poor performance at three days and that were tested again at eighteen days displayed similar avoidance behavior at eighteen days as their sham-operated controls. The results suggest that pituitary stalk section impairs performance of an active avoidance response. The transient nature of this effect may be due to disruption and subsequent regeneration of vascular contact between pituitary and brain.

Animals↗
PubMed1983

Intravenous maprotiline in severe and resistant primary depression: a double-blind comparison with clomipramine.

A double-blind, randomized trial is described which was designed to compare the clinical effect of 100 mg daily of maprotiline (Ludiomil) and of clomipramine (Anafranil) given by the intravenous route in forty hospitalized female patients with severe and resistant primary depression. Physicians' assessment of patients' progress was made following 5, 9 and 21 days of treatment. The response rates to maprotiline and clomipramine were not significantly different even if a greater number of patients responded to clomipramine. None of the demographic and clinical variables considered could be identified as factor predicting the response to maprotiline and to clomipramine, even if a trend for a preferential responsiveness to clomipramine in the older patients was observed.

Adolescent↗
PubMed1983

Role of prolactin-opiate interactions in the central regulation of pain threshold.

Endogenous hyperprolactinaemia induced by anterior pituitary transplantation under the kidney capsule has been found to reduce the behavioural responsiveness to electrical footshock and to increase morphine-induced analgesia. The apparent analgesic effect of prolactin has been related to the stimulation of nigro-striatal dopaminergic transmission, as suggested by the increase in striatal dopamine turnover observed in hyperprolactinaemic rats. It seems likely that central opiate system is involved in the behavioural effects of prolactin. Thus, naloxone prevents the effects of hyperprolactinaemia on footshock responsiveness and heroin self-administration is decreased in hyperprolactinaemic rats.

Animals↗
PubMed1982

Behavioral responses of long-term hyperprolactinaemic rats.

Rats with long-term endogenous hyperprolactinaemia induced by pituitary homografts under the kidney capsule displayed an enhancement of amphetamine- and apomorphine-induced stereotypy, a facilitated acquisition of active avoidance behavior and a decreased responsiveness to electrical footshock. However, no difference between homografted and sham-operated rats was observed with respect to grooming behavior. It is concluded that at least two processes occur during prolonged hyperprolactinaemia, i.e. development of tolerance to prolactin with respect to enhanced grooming activity and of supersensitivity of postsynaptic dopaminergic receptor systems. These two processes may be dependent or independent from each other.

Adrenal Glands↗
PubMed1982

Endogenous hyperprolactinaemia and avoidance behaviors of the rat.

The influence of endogenous hyperprolactinaemia induced by pituitary homografts under the kidney capsule on conditioned avoidance behaviors of the rat has been investigated. Acquisition of active avoidance behavior, as studied in shuttle-box and pole jumping test situations, appeared to be facilitated in homografted rats in comparison with sham-operated animals. Extinction behavior was not affected in the same tests. Retention of one-trial learning passive avoidance behavior in homografted rats was similar to that of sham-operated animals. Hyperprolactinaemia resulted in a diminished behavioral responsiveness to electrical footshock. It is concluded that endogenous hyperprolactinaemia selectively affects acquisition, but not retention performance of avoidance behaviors.

Animals↗
PubMed1982

Aromatization of testosterone by adipose tissue and sexual behavior of castrated male rats.

The influence of aromatization of testosterone occurring in adipose tissue has been studied in castrated obese male rats. The treatment for 30 days with a subliminal dose (115 micrograms/kg per day) of testosterone propionate improved significantly the sexual performance of castrated obese male rats as compared to the nonobese controls. Untreated castrated obese animals did not show any enhancement of sexual behavior. Furthermore, obesity failed to improve sexual performance in intact male rats. Measurements of plasma levels of testosterone and 17 beta-estradiol showed an increase in aromatization of testosterone in obese rats. Present data suggest that adipose tissue can be considered an important site for aromatization of testosterone to 17 beta-estradiol, and that aromatization is involved in the activation of sexual behavior in castrated male rats.

Adipose Tissue↗
PubMed1981

Endogenous hyperprolactinaemia enhances amphetamine- and apomorphine-induced stereotypy.

Rats with endogenous hyperprolactinaemia induced by pituitary homografts under the kidney capsule were more sensitive to amphetamine and apomorphine with respect to drug-induced stereotypy, while a normal response was noted in drug-induced changes of locomotor activity, rearing and grooming. It is suggested that postsynaptic dopaminergic receptors, probably in the nigro-striatal system, may become selectively supersensitive in the endogenous hyperprolactinaemic animals.

Amphetamine↗
PubMed1981

Possible role of prolactin in the modification of medial basal hypothalamic glutamic acid decarboxylase activity.

The effects of acute and chronic injections of haloperidol, sulpiride and apomorphine on serum prolactin (PRL) levels and medial basal hypothalamus (MBH) glutamic acid decarboxylase (GAD) activity were investigated in male rats. Parallel changes in PRL and GAD activity were observed in acutely treated animals. Conversely, a return to normal of the GAD activity associated with high plasma PRL levels was induced by chronic haloperidol and sulpiride treatment. Results are discussed in the light of the possible existence of a hypothetical PRL-gamma-aminobutyric acid (GABA) subsidiary feedback loop.

Animals↗
PubMed1981

Prolactin induces grooming in the rat: possible involvement of nigrostriatal dopaminergic system.

The possibility that Prolactin-induced grooming involves the nigrostriatal dopaminergic system was studied. Intracerebroventricular injection of rat Prolactin (PRL) in an amount of 10 micrograms induced grooming in male rats, and neostriatal injection of haloperidol (1 microgram/1 microliter) markedly suppressed this effect. Local administration of 6-OHDA in the substantia nigra also abolished the influence of intracerebroventricularly administered PRL. Bilateral injections of PRL (10 micrograms/l microliters) in the neostriatum failed to induce grooming, whereas bilateral injections of peptide into the substantia nigra (1 microgram/0.5 micrograms) elicited the behavioral response. It is probable that PRL induces grooming in the rat by interacting with the nigrostriatal dopaminergic transmission through an action on the cell bodies rather than in presynaptic terminals or at the postsynaptic level of this system.

Animals↗
PubMed1981

Behavioral effects of phosphatidylserine in aged rats.

The behavioral effects of 5 days of administration of phosphatidylserine (PS) was studied in aged rats. The intraperitoneal (5, 10, and 20 mg/kg) or intracerebroventricular (5, 10, and 20 micrograms/2 microliters) injection of PS liposomes caused a facilitated acquisition of active avoidance behavior as studied in shuttle-box and pole jumping test situations. The retention of active and passive avoidance responses was also improved. No substantial difference between PS-treated and control animals was apparent either in the responsiveness to electrical footshock or in the motor activity tested in an open field. Grooming behavior appeared to be enhanced in rats treated with the highest dose of the substance. Since PS affects both central catecholaminergic and cholinergic transmission, which is known to be impaired in old animals, the possibility that the behavioral effects of PS involve brain dopamine and/or acetylcholine systems is discussed.

Aging↗