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Biomedical subjects

C Castellano

Publications and source records attributed to C Castellano.

At least 109 records · Page 6Linked to original sources
PubMed1985

Effects of sauvagine on behavioural arousal of mice.

The effects of natural and synthetic sauvagine on locomotor activity and ECS-induced seizures were studied in DBA/2 mice. A dose-dependent activity depression was evident following the administration of both compounds. Moreover they exerted a protective effect against ECS-induced seizures. This effect was naloxone-reversible, suggesting the involvement of endogenous opioids. In both series of experiments natural sauvagine was more effective than the synthetic compound.

Amphibian Proteins↗
PubMed1985

Dose- and strain-dependent effects of dermorphin and [D-Ala2-D-Leu5]enkephalin on passive avoidance behavior in mice.

Dermorphin and [D-Ala2-D-Leu5]enkephalin, administered intracerebroventricularly (icv) immediately after training in a passive avoidance test, exerted dose- and strain-dependent effects in DBA/2 (DBA) and C57BL/6 (C57) mice. In fact, the peptides impaired, at a low dose (5 ng), the retention performances of both strains; a higher dose (50 ng) impaired retention in DBA but improved it in C57 mice. A dose of naloxone (0.3 microgram, icv), which was ineffective when administered alone, antagonized the effects observed. The results are discussed in terms of strain differences in central mechanisms.

Analgesics, Opioid↗
PubMed1985

Improvement of avoidance acquisition by the nootropic drug oxiracetam in mice.

The nootropic drug, oxiracetam (25 or 50 mg/kg i.p.), was tested in two inbred strains of mice, subjected to shuttle-box avoidance training. The drug improved avoidance acquisition in good performers BALB/c mice more than in poor performers C57BL/6 mice. In both cases the avoidance facilitating action was evident only if training was preceded by a five-day pretreatment. The nootropic prototype, piracetam (100 mg/kg), facilitated avoidance acquisition in pretreated BALB/c, but not in C57BL/6 mice.

Animals↗
PubMed1985

Effects of bremazocine on locomotor activity in DBA/2 and C57BL/6 mice.

The effects of the benzomorphan analogue bremazocine on locomotor activity were studied in DBA/2 (DBA) and C57BL/6 (C57) mice. Three sets of experiments were carried out. In a first set, bremazocine depressed activity in both strains, but DBA mice were more sensitive to the effects of the drug. In a second set of experiments the effects of bremazocine were antagonized by a per se ineffective dose (0.5 mg/kg) of the selective kappa-opioid receptor antagonist MR 1452, showing that they were mediated through an interaction with this sub-population of opioid receptors. In a third set of experiments the effects of bremazocine were enhanced by the administration of a per se ineffective dose (0.025 mg/kg) of haloperidol, showing the involvement of dopaminergic mechanisms.

Analgesics↗
PubMed1984

Naltrexone-reversible effects of flunitrazepam on locomotor activity and passive avoidance behaviour in mice.

Some behavioural effects of flunitrazepam were investigated in two sets of experiments in C57BL/6 mice. In the first set, flunitrazepam administration (0.025 or 0.05 mg/kg) enhanced the locomotor activity of mice. In the second set, memory impairments were observed following posttraining (immediately or 30 min, but not 60 min) treatment with the drug (0.05 mg/kg). All effects were antagonized by a per se ineffective dose of naltrexone (0.5 mg/kg for the activity, 0.1 mg/kg for the memory experiments), suggesting the involvement of opioid receptors. The results are discussed on the basis of recent evidence suggesting a link between benzodiazepine and opiate mechanisms of action.

Animals↗
PubMed1984

Prenatal exposure to morphine in mice: enhanced responsiveness to morphine and stress.

Some behavioral effects of prenatal morphine administration were studied in CD1 mice. Two sets of experiments were carried out. In a first set, which was performed during development: (a) measures of postnatal reflexes revealed only a light deficit in tests involving motor control, (b) activity measures showed a significant reduction of spontaneous activity which was evident only in the course of the first postnatal days. In a second set of experiments, in which adult mice were tested for activity, analgesia and passive avoidance learning: (a) no difference was observed, in baseline conditions, between the performances of the mice prenatally exposed to saline and those preexposed to morphine, (b) as compared with controls, enhanced responsiveness to morphine administration (for the activity and passive avoidance measures), and to morphine and stress (for the analgesic measures) were found.

Analgesia↗
PubMed1984

Opioid antagonism of electroshock-induced seizures.

Morphine, beta-endorphin and [D-Ala2, D-Leu5] enkephalin administered intracerebroventricularly exerted a protective effect on electroconvulsive shock (ECS)-induced seizures in mice. This effect was reversed by intraperitoneal injections of naltrexone. The role of mu and delta receptors in ECS-induced convulsions is discussed.

Animals↗
PubMed1984

Morphine and memory in DBA/2 mice: effects of stress and of prior experience.

In a first set of experiments, immediately post-training morphine (1.0 or 2.5 but not 0.5 mg/kg) treatment, or immobilization stress (30 or 60 but not 15 min) impaired memory processes of non-pretrained DBA/2 mice tested in a passive avoidance box. The effects were naloxone-reversible and time-dependent (they were absent in mice injected with morphine, or immobilized, starting 120 min after training). No effect was evident in no-footshock groups injected with morphine (2.5 mg/kg) or immobilized (60 min), thus showing lack of proactive influence of the treatments on performance. In a second set of experiments, in which pretrained animals were used, both morphine and immobilization stress were less effective in disrupting memory processes of mice. In both sets of experiments a per se ineffective stress enhanced the effects of morphine. A number of possible hypotheses concerning the results obtained are examined. In particular the possible role of emotional factors in the effects of morphine on memory is discussed.

Animals↗
PubMed1984

Locomotor depression by the opioid benzodiazepine tifluadom in mice.

Several doses of tifluadom, an opioid benzodiazepine with affinity for opioid kappa receptors, were tested on analgesia and locomotor activity in two strains of mice, the C57BL/6 and the DBA/2. The analgesic properties of the compound were confirmed in both strains by a tail flick test. As concerns locomotor activity both strains, that in previous researches showed opposite responses to opiates, were depressed by tifluadom, suggesting the involvement of kappa receptors in this effect.

Analgesia↗
PubMed1984

Effects of DL-allylglycine, alone or in combination with morphine, on passive avoidance behaviour in C57BL/6 mice.

In a first set of experiments the posttrial intraperitoneal acute administration of the GAD-inhibitor DL-allylglycine impaired the memory processes of C57BL/6 (C57) mice tested in a passive avoidance apparatus. Memory improvements were, on the contrary, observed following morphine treatment. These effects were dose- and time-dependent. They were, in particular, evident if mice were injected immediately, or 30 min, but not 60 min, after training in the apparatus, and were absent in the no-footshock groups, suggesting lack of proactive effects of the drugs on performance. In a second set of experiments, the posttraining administration of allylglycine, at a per se ineffective dose (5 mg/kg), antagonized the memory improvement exerted by the administration of morphine (0.5 or 1.0 mg/kg). The results support the hypothesis of an involvement of GABAergic mechanisms in the memory consolidation processes, and suggest the possibility that GABAergic systems play a role in the effects of morphine on memory in C57BL/6 mice.

Allylglycine↗
PubMed1983

Anticonvulsant effects of stress: role of endogenous opioids.

Mice subjected to immobilization stress were protected against electrconvulsive shock-induced seizures in comparison to non-stressed mice. Pretreatment with naltrexone antagonized the effects of stress indicating that the protective effects of stress on seizures involved a release of endogenous opioids.

Animals↗
PubMed1983

Strain-dependent modulation of memory by stress in mice.

The effects of immobilization stress were investigated in Swiss Webster (Swiss), DBA/2 (DBA), and C57BL/6 (C57) mice, tested in a passive avoidance situation. Retention performance was impaired in Swiss and DBA mice, and improved in C57 mice, immobilized immediately, but not 2 hr, after training. These effects lasted for less than 7 days in DBA and Swiss mice, while they were still present, in the C57 strain, 14 days after training. The naloxone antagonism of the effects observed was also demonstrated. The results are discussed in terms of the possible role of endogenous opioids, stress hormones, and genetic makeup in the stress-induced modulation of memory processes in the mouse.

Animals↗
PubMed1982

Opiate analgesia: evidence for circadian rhythms in mice.

The effects of a 12-12 h light-dark (L-D) cycle and of constant light (L-L) on nociceptive thresholds and morphine-induced analgesia were studied in two strains of mice: C57BL/6 and SEC/1Re. Under the L-D condition, a diurnal rhythm was observed in the responsiveness of mice to nociceptive stimuli, and in the analgesic effects of morphine. Under the L-L schedule clear patterns of daily rhythmicity were evident in both strains for both nociceptive thresholds and responsiveness to morphine. Finally, under the L-L schedule, the overall responsiveness to pain and the antinociceptive effects of morphine were clearly increased in comparison to the patterns evident in the L-D condition. The administration of naloxone decreased the nociceptive thresholds, thus indicating an involvement of the endogenous opioid peptides. These phenomena are discussed in terms of the different pacemaker mechanisms involved in the expression of various patterns of daily behavioral and neurochemical rhythmicity in these strains, and of the effects of light in controlling the release of endogenous opioids.

Animals↗
PubMed1982

Behavioural data on dermorphins in mice.

Dermorphin, an opioid peptide occurring in amphibian skin, exerted a depressive effect on locomotor activity of C57B1/6 mice and an analgesic effect when injected intravenously. Intracerebroventricular injections of dermorphin enhanced locomotor activity and resulted in analgesia. A stimulating effect of intracerebroventricular administration on locomotor activity was also induced by shorter homologues of dermorphin and [D-Ala2, Leu5]enkephalinamide, while beta-endorphin produced a depression. It is suggested that dermorphin acts on central receptor populations activated by morphine and enkephalins.

Animals↗
PubMed1982

Classical conditioning of stress-induced analgesia.

Exposure of mice to a series of inescapable shocks produced analgesic reaction. This type of naloxone reversible, stress-induced analgesia responds to classical conditioning. Stress-induced analgesia involves activation of the opiate system: thus this type of analgesic mechanism responds to classical conditioning.

Animals↗
PubMed1982

Effects of naloxone and naltrexone on locomotor activity in C57BL/6 and DBA/2 mice.

Administration of naloxone or naltrexone in DBA/2 (DBA) mice was followed by dose related depressant effects. The locomotor activity of the C57BL/6 (C57) mice injected with naltrexone was also depressed. Low doses of naloxone induced a decrease in activity in the C57 strain. This effect gradually disappeared at intermediate doses and recurred again at higher doses. The results are discussed in terms of differences in type number and/or distribution of the receptors influenced by naloxone and naltrexone in the two strains of mice tested.

Animals↗