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Biomedical subjects

C Spadaro

Publications and source records attributed to C Spadaro.

At least 19 recordsLinked to original sources
PubMed1991

Effect of indomethacin on opioid-induced gastric protection in cold-restrained stress.

Morphine and the synthetic opioid met-enkephalin analog [D-Ala2, MePhe4, Met(0)5ol] enkephalin (FK 33-824) injected intraperitoneally to rats at doses of 5-20 and 0.5-2 mg/kg respectively showed a protective effect on gastric lesion induced by cold-restraint stress. This protective effect was abolished by pretreatment with indomethacin. This suggests a role for prostaglandins in the protection, induced by opioids of the gastric mucosa against the development of stress-induced ulcers.

Animals↗
PubMed1990

Modification of rat thermal responses to morphine by alpha-FMH suggests a role for neural histamine in morphine tolerance.

In rats, morphine may either raise or lower body temperature depending on the dose. A morphine dose of 50 mg/kg, i.p., consistently produced a nearly maximal hypothermic response in non tolerant rats, whereas this dosage induced an elevation of body temperature in tolerant rats. In rats pretreated with alpha-fluoromethylhistidine (alpha-FMH), an irreversible inhibitor of histidine decarboxylase which induces a reduction in brain histamine synthesis, this morphine dose of 50 mg/kg, i.p. produced an elevation of rectal temperature resembling that observed in morphine-tolerant rats. To confirm the suggestion that hyperthermic effects of the higher dose of morphine in morphine-tolerant rats or in alpha-FMH-pretreated rats could be related to a possible involvement of mediators of fever, e.g. prostaglandins, animals were pretreated with acetylsalicylic acid (aspirin, Bayer) 30 mg/kg, i.p., 60 min before morphine. Results showed that acetylsalicylic acid prevented the hyperthermic response of morphine, resulting in a fall in body temperature. Since morphine releases histamine and alpha-FMH inhibits histamine synthesis, our data demonstrating that an inhibitor of prostaglandin-synthetase showed efficacy only in animals responding with fever to the higher dose of the opiate, suggests a physiological antagonism between histamine and prostaglandins on mechanisms underlying hyper/hypothermic responses to morphine.

Animals↗
PubMed1987

Evidence of correlations between mast-cell histamine and beta-endorphin (ir) from NIL-pituitary in the homeostasis.

This study was designed to characterize physiological events related to a single or repeated experimental anaphylactoid reactions (by Compound 48/80) in non-stressed or cold-restrained rats. Acute treatment with Compound 48/80 (1 mg/kg, i.p.) increases Beta-endorphin(ir) content in the neurointermediate lobe (NIL) of rat pituitary. Moreover, repeated treatment with Compound 48/80 showed tolerance effects. These animals, exposed to stressful conditions, exhibited a fully evident paw oedema following carrageenin oedema-test, whereas saline-pretreated rats, under the same experimental conditions, showed reduced local inflammation. Since Compound 48/80 produces characteristic, systemic, anaphylactoid reaction in the rat, with a very high degree of selectivity in its action, our results suggest that mast-cell histamine and Beta-endorphin from NIL pituitary are involved in the body's reactivity to stressful stimuli.

Animals↗
PubMed1987

Effects of morphine and met-enkephalin analogue on gastric lesions induced by indomethacin.

The effects of morphine HCl and a synthetic met-enkephalin analogue [D-Ala2,MePhe4,Met(O)5ol]enkephalin (FK 33-824) on gastric damage produced by the intraperitoneal administration of indomethacin (10 mg/kg i.p.) have been investigated. Rats intraperitoneally pretreated with morphine HCl (10 mg/kg i.p.) and FK 33-824 (1 mg/kg i.p.) showed a statistically significant reduction both of the number and intensity of lesions induced by indomethacin. This protection was reversed by naloxone HCl (2 mg/kg i.p.). The protective effect was not related to a reduction of gastric secretion since the antisecretory drug cimetidine (25 mg/kg i.p.) and methscopolamine bromide (10 mg/kg i.p.) did not significantly prevent mucosal damage under the same experimental conditions.

Animals↗
PubMed1985

Studies on the antinociceptive effect of intrathecal salmon calcitonin.

The involvement of spinal opioid receptors and spinal monoaminergic systems, in the antinociceptive effect of intrathecal (IT) salmon calcitonin, has been evaluated by means of the hot plate test, in the rat. Intrathecal pretreatment with 40 micrograms MR 1452 and 40 micrograms ICI 154,129, purported selective antagonists respectively for kappa and delta opioid receptors did not modify sCT-induced antinociception (2 micrograms IT). A delay in the development of IT sCT-induced antinociception was observed in rats selectively depleted of cord serotonin (25 mg/kg IP desipramine plus 100 micrograms IT 5,7-dihydroxytryptamine), whereas the administration of serotonergic antagonists, methysergide and ketanserin, 30 micrograms IT, did not influence sCT effect. Cord catecholamine depletion (6-OHDA pretreatment) reduced significantly sCT antinociception. A similar reduction was produced by the dopaminergic antagonist haloperidol (15 micrograms IT), but not by the alpha-blocker phentolamine (15 micrograms IT). Findings of this study rule out an involvement of opioid peptidergic system in sCT-induced increase of hot plate latencies at spinal level; a possible involvement of cord dopaminergic receptors is suggested.

Analgesics↗
PubMed1981

[Erythrocyte indices in smokers and heroin addicts].

Red blood cells values of 100 male heroin addicts, 100 male smokers and 100 normal men, all of like age, have been examined. Nearly all of the heroin addicts are heavy cigarette smokers. The GRC/mm3, Hb g%, Ht%, MCHC and MCV values did not show significant statistical differences between the three groups, except the MCV in the average appeared 2,8 mu3 higher in the smokers, than the normal non smokers. In heroin addicts there did not appear any variation related to abnormalities in liver function and dependency life time. The differences between the results of our studies and the literature are determined from a longer exposition to the damage caused from heroin and smoke.

Adolescent↗
PubMed1980

Changes in opiate activity of rat pituitary following acute administration of neuroleptics.

An increase was found in the opiate activity of pituitary extracts obtained rom rats injected with the neuroleptic drugs trifluoperazine and sulpiride. The increase of opiate activity, measured by bioassay, was particularly evident 2 h after the administration of sulpiride. Dexamethasone completely prevented the neuroleptic-induced effect. Trifluoperazine and sulpiride may have affected dopaminergic mechanisms regulating endorphin storage in the pituitary.

Animals↗
PubMed1979

Prostaglandins in the brain of rats given, acutely, and chronically, a hyperthermic dose of met-enkephalin.

An enhanced prostaglandinlike activity is shown in homogenates of brain from rats treated intracerebroventricularly with 100 microgram of metenkephalin. The increase is significantly reduced by naloxone pretreatment. A relationship is proposed between generation of prostaglandins in the brain following met-enkephalin administration and hyperthermic effect of the opiatelike factor in the rat. Normalization of prostaglandinlike activity following chronic administration of met-enkephalin in the rat may also account for the development of tolerance to its thermic effect.

Animals↗
PubMed1979

Prostaglandins in rat placenta following acute and chronic administration of morphine.

The objective of the present study was to obtain information on prostaglandin (PG) biosynthesis in placenta following narcotic administration. PG biosynthetic capacity was determined in whole rat placenta homogenates in the presence of Na arachidonate, by evaluating net production of PGs assayed against PGE1 on rat stomach strips. An enhanced prostaglandin-like activity is shown in homogenates of placenta from rats treated subcutaneously with 10 mg/kg of morphine. This increase was prevented by naloxone pre-treatment. Continual morphine administration during gestation, results in a normalization of placental biosynthetic capacity thus suggesting the development of a tolerance to the narcotic effect.

Animals↗
PubMed1978

Effects of Met-enkephalin on body temperature of normal and morphine-tolerant rats.

The endogenous opioid met-enkephalin intraventricularly adminstered to the rat at the dose of 100 microgram raised rectal temperature, whereas 400 microgram of the pentapeptide caused a diphasic effect, i.e., hypothermia followed by hyperthermia. Met-enkephalin was ineffective when administered i.p. The effects on temperature were substantially similar to those elicited, for both routes of administration, by morphine, which may either raise or lower rat temperature depending on the dose. More naloxone was required to antagonize thermic effects of met-enkephalin than morphine. Finally, there was a lack of effects on temperature for met-enkephalin centrally administered to morphine-tolerant animals, thus providing further evidence, in vivo, of cross tolerance between opiates and naturally occurring ligands of opiate receptors.

Animals↗
PubMed1978

Changes in liver tyrosine aminotransferase after acute and chronic administration of morphine in the rat.

Acute administration of Morphine (20 mg/kg/s.c.) in the rat results in a rise of liver tyrosine aminotransferase (TAT) expressed as mumoles of p-hydroxyphenylpyruvate/100 mg/h. With chronic administration, a tolerance develops to this enzymatic effect. TAT induction is not evident in pregnant rats, given the narcotic, in which enzyme levels are already initially high. After delivery TAT returns to normal levels and it is possible to show both induction and tolerance developing to morphine. Enzyme activity in fetal livers is much lower than that of adult animals: after maternal administration of morphine only a modest TAT increase is seen which is not, however, statistically significant. TAT activity is fully evident in livers of offspring, with much higher mean levels in newborn rats from morphine-treated animals, as a possible consequence of morphine deprivation. In this latter group of newborn rats narcotic administration causes TAT activity to return to levels as high as those of naive animals. On the other hand, morphine administration to the prole of naive rats results in an induction of liver TAT.

Animals↗