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Biomedical subjects

R Poggioli

Publications and source records attributed to R Poggioli.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Endogenous anti-analgesic systems].

Nociception is of vital importance for the organism, while its inhibition by endogenous opioid systems is usually a sign of surrender. Therefore, it must be assumed that endogenous analgesic systems are balanced, and in fact, under normal conditions, overwhelmed, by teleologically far more important anti-analgesic systems. The two main anti-analgesic systems--i.e., the melanotropinergic and the cholecystokininergic--are here reviewed for their role, not only in nociception, but in a wide variety of vital functions (endocrine, gastrointestinal, ingestive, reproductive, cardiovascular, immune, etc.). Available data strongly suggest that these systems (particularly the melanotropinergic one) play a key role in the overall homeostasis of the body. Moreover, modulation of endogenous anti-analgesic systems may disclose a new, unforeseen approach to the treatment of pain.

Analgesia↗
PubMed1993

The behavioral syndrome induced by adreno corticotropic hormone in rats is prevented by Ca++ channel blockade.

The most typical signs (stretchings, yawnings, penile erections, excessive grooming) of the behavioral syndrome induced in rats by the intracerebroventricular administration of ACTH- (1-24) (4 micrograms/rat) were dose-dependently antagonized by the intraperitoneal injection of the selective Ca++ channel inhibitor, nicardipine (dose range: 0.1-1 mg/kg). These data suggest that the influx of Ca++ into target neurons is a step of key importance for the occurrence of ACTH-induced behavioral signs, and that Ca++ may play the role of second intracellular messenger for the behavioral effects of melanocortins.

Animals↗
PubMed1992

Galanin inhibits sexual behavior in male rats.

Intracerebroventricular injection of galanin potently inhibited (0.5 micrograms/rat) or completely suppressed (5.0 micrograms/rat) copulatory activity in sexually experienced male rats, without producing any other obvious behavioral deficit. It is suggested that galanin, known to potently stimulate feeding behavior, may be involved in the inverse modulation of feeding and sexual behaviors.

Animals↗
PubMed1992

Behavioral effects of atriopeptin in rats.

High densities of atriopeptin-immunoreactive fibers and of highly specific and selective atriopeptin receptor sites are present in brain areas involved in animal behavior. The possible influence of these peptides on behavior was thus investigated in adult rats. The intracerebroventricular injection of atriopeptin II modified male sexual behavior (reduction in mount latency) at the dose of 5 micrograms/animal; lower and higher doses were ineffective. Open-field behavior was also modified by i.c.v. atriopeptin II at the doses of 5 and 10 micrograms/rat, which induced an increase in the number of external and internal crossings and of external rearings. Finally, in fasted rats, atriopeptin II, at the dose of 10 micrograms/rat, significantly increased the amount of food intake 30 and 60 min after injection. These findings indicate that atriopeptins may modify different animal behaviors.

Animals↗
PubMed1991

Influence of the selective cholecystokinin antagonist L-364,718 on pain threshold and morphine analgesia.

The intracerebroventricular injection of the cholecystokinin-A receptor antagonist L-364,718, at the doses of 0.5, 5, 10 or 20 micrograms/mouse, while having no effect on pain threshold (hot plate, 51 degrees C), antagonized the analgesic activity of morphine (10 mg/kg i.p.). This effect was obtained with a dose of 10 micrograms/mouse and was associated with a reduction of brainstem opiate-binding sites.

Analgesia↗
PubMed1990

Inhibition of feeding by ACTH-(1-24): behavioral and pharmacological aspects.

The time course of the behavior of rats fasted for 24 h was analyzed with observation starting either 10 or 60 min after the i.c.v. administration of ACTH-(1-24) (4 micrograms/animal). The anorectic effect of this peptide was direct and specific because it could be dissociated in time from the grooming-inducing effect. The effect is a central one, not linked either to an interaction with the peripheral feeding-regulatory system, or to the release of adrenal steroids. ACTH-(1-24), like corticotropin-releasing factor (CRF), is capable of antagonizing the stimulation of feeding seen during starvation, insulin (10 IU/kg s.c.)-induced hypoglycemia, stimulation of GABAergic (muscimol, 250 ng/rat i.c.v.), noradrenergic (norepinephrine, 20 micrograms/rat i.c.v.) or opioidergic systems. The data suggest that both CRF and ACTH may be considered as putative mediators in the production of stress-induced anorexia.

Adrenalectomy↗
PubMed1990

NPY-induced inhibition of male copulatory activity is a direct behavioural effect.

In adult, sexually-experienced male rats, the intracerebroventricular injection of NPY caused a dose-related inhibition of copulatory behaviour, all parameters (mount, intromission and ejaculation latencies, mount and intromission frequencies, mean inter-intromission interval, post-ejaculatory interval) being significantly worsened at the dose of 8 micrograms/rat. Since rats were deprived of food during the behavioural test, it is concluded that inhibition of sexual behaviour is a 'true', direct behavioural effect of NPY, not due to a shift towards increased feeding.

Animals↗
PubMed1986

Morphine and beta-endorphin antagonize posture and locomotor disorders induced by the injection of ACTH 1-24 in the rat locus coeruleus.

The unilateral microinjection of ACTH 1-24 (20 nmol) into the locus coeruleus (LC) produced a long lasting (2-3 hr) posture asymmetry and movement disorder in all rats tested. This response was readily suppressed by the subsequent local microinjection of an equimolar dose of beta-endorphin or morphine or by the intraperitoneal injection of morphine sulphate (50 mg/kg). Microinjection of naloxone (20 nmol) into the LC produced the above syndrome in a lower percentage of animals. The results support the hypothesis that ACTH peptides and opioids play opposite roles in the control of different brain functions.

Adrenocorticotropic Hormone↗
PubMed1986

Sodium deprivation increases the antinociceptive activity of morphine.

In rats maintained for 50 days on a low-sodium diet and with a compensatory hyperactivity of the renin-angiotensin system, the antinociceptive activity of morphine was significantly longer-lasting than in controls. It is suggested that the renin-angiotensin system modulates opioid system responsivity.

Analgesics↗
PubMed1985

Influence of yohimbine on the ACTH-induced behavioural syndrome, in rats.

In adult male rats, yohimbine at low doses (0.1, 0.5 and 1 mg/kg i.p.) potentiated, and at high doses (30.0 mg/Kg) antagonized, the behavioural syndrome induced by the intracerebroventricular injection of ACTH 1-24 (3 micrograms/rat) (stretching-yawning syndrome and penile erections). These results support the hypothesis that brain catecholaminergic systems play a positive role in the ACTH-induced behavioural syndrome.

Adrenocorticotropic Hormone↗
PubMed1984

Influence of clonidine on the ACTH-induced behavioral syndrome.

In male rats, clonidine in a dose range of 1-3000 micrograms/kg i.p. antagonized the stretching-yawning syndrome induced by the intraventricular injection of ACTH-(1-24) (3 micrograms/rat) dose-dependently. On the other hand, the effect of clonidine on ACTH-induced penile erections was potentiation at low doses (5 and 10 micrograms/kg) and inhibition at the highest doses (1000 and 3000 micrograms/kg), the intermediate doses (50 and 100 micrograms/kg) being without effect. There was no relationship between these behavioral effects and the effect on arterial blood pressure.

Adrenocorticotropic Hormone↗
PubMed1984

Sexual behavior of male rats: influence of short- and long-term adrenalectomy.

Adult male rats (3 months old) were tested for their copulatory behavior: those satisfying the criterion of sexual vigor in the last three out of five weekly tests were randomly divided into two groups and adrenalectomized or sham operated, and their copulatory activity was retested 35 and 420 days after surgery. Short-term adrenalectomy did not modify any of the parameters of sexual behavior. On the other hand, a higher percentage of adrenalectomized than of sham-operated rats still had successful sexual performance when 18 months old (420 days after surgery); moreover, blood levels of testosterone were higher in adrenalectomized than in sham-operated old rats. The possibility that adrenal steroids may play a role in the age-linked decline in male sexual activity in mammals is discussed.

Adrenal Glands↗
PubMed1983

Antidepressants and opiates interactions: pharmacological and biochemical evidences.

Imipramine, chronically administered to rats (20 mg/Kg/day X 20) has a potent analgesic effect per se (hot plate test), increases morphine analgesia and intensifies morphine withdrawal syndrome precipitated by naloxone. Receptor binding studies performed with 3H-naloxone revealed that chronic administration of imipramine results in a marked increase of opiate binding sites in the brain. This increase persisted when the rats treated chronically with imipramine were rendered tolerant to morphine by s.c. implantation for 3 days of a pellet containing 100 mg of morphine. Since antidepressants exert their own analgesic effect, increase morphine analgesia and displace opiate receptor binding, it may be that by interacting with the opiate receptor complex imipramine induces supersensitivity in opiate recognition binding sites.

Analgesics↗
PubMed1982

Influence of 2,4-tetra-O-methyl-furfurylidene-sorbitol (MSF) on carrageenan-induced inflammation and anti-inflammatory and toxic effects of indomethacin in rats.

The influence of the free radical scavenger 2,4-tetra-O-methyl-furfurylidene-sorbitol (MSF) on the carrageenan-induced hind-paw inflammation in rats as well as its influence on the anti-inflammatory and toxic activities of indomethacin is evaluated in comparison with thiola, thioctic acid, silymarin, reduced glutathione and propylgallate. MSF has been previously shown to prevent, in rats, the liver damaging effects of CCl4, ethionine, allylic alcohol and amanita phalloides row extracts. MSF, but not the other scavengers, exhibits moderate anti-inflammatory properties and markedly potentiates the anti-inflammatory activity indomethacin. Further MSF, but not the other scavengers, reduces some expressions of indomethacin toxicity such as gastric mucosal damage, intestinal hemorrhage and peritoneal fluid accumulation and ensuing death. Since MSF shares a number of pharmacological properties with vitamin E, which also increases indomethacin anti-inflammatory activity while reducing indomethacin toxicity, it is suggested that MSF has this for its vitamin E-like activity perhaps as a result of altering the arachidonic acid cascade.

Animals↗