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Biomedical subjects

A Oliverio

Publications and source records attributed to A Oliverio.

At least 73 records · Page 4Linked to original sources
PubMed1983

Social isolation: effects on pain threshold and stress-induced analgesia.

Individually housed DBA/2 mice showed higher pain thresholds than grouped mice. Stress-induced analgesia was evident in grouped but not in isolated mice. Since also morphine injections did not result in analgesic effects in isolated mice, it is suggested that social isolation results in an increased release of opioids which may produce a decreased sensitivity at the opiate receptor level. The role of endogenous opioids in relation to social isolation is discussed.

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

Circadian variations of noradrenaline, 5-hydroxytryptamine and dopamine in specific brain areas of C57Bl/6 and BALB/c mice.

Daily variations in noradrenaline, 5-hydroxytryptamine and dopamine turnover were evident in two strains of mice (C57Bl/6 and BALB/c) subjected to 12-12 h light-dark cycles. These fluctuations were also evident under continuous light (L-L) in C57Bl/6 mice only, a strain which is characterized by clear-cut circadian wheel running activity in the absence of external synchronizers.

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

Dopamine receptors in the striatum and limbic system of various strains of mice: relation to differences in responses to apomorphine.

Dopamine receptors, defined as [3H]spiroperidol binding sites, had similar population parameters in the limbic forebrain of C57BL/6, Albino Swiss and DBA/2 mice, but the parameters of the striatal populations were different: not only the densities differed among themselves, but the KD value of the striatal dopamine receptors of DBA/2 mice was significantly higher than that in the two remaining strains. Behavioral responses of Albino Swiss mice to apomorphine: biphasic effect of apomorphine on locomotor activity and stereotypy characterized by high motility, frequent rearing and sharp, not very frequent bites, were similar to those described earlier for C57BL/6 mice, and differed from those reported for DBA/2 mice. The results suggest that the difference in responding to apomorphine in various strains of mice may be related to differences in their striatal dopamine receptors.

Animals↗
PubMed1982

Effects of opiate antagonists on social and aggressive behavior of isolated mice.

Opiate antagonists naloxone (1 and 1.5 mg/kg IP) and naltrexone (2.5 and 5 mg/kg IP) inhibit aggressive responses of DBA/2 isolated mice, while increasing the duration of some social activities such as sniff-body, sniff-nose and following. At the doses employed naloxone and naltrexone did not affect motor activity and self-grooming of paired mice. These findings are discussed in terms of the endogenous opioids system involvement in arousability, in the response of the organism to stressful events, in the motivational mechanisms which control social behavior and in the functioning of some neurotransmitter systems which are known to play an important role in the control of isolation-induced aggressive behavior.

Aggression↗
PubMed1982

Analysis of the difference in the behavioral effects of apomorphine in C57BL/6 and DBA/2 mice.

The influence of pimozide on the effects of apomorphine on locomotor activity and stereotypy was studied in two inbred strains of mice. In C57BL/6 mice, in which apomorphine did not produce stereotypy of gnawing, the biphasic effect of apomorphine on locomotor activity (hypomotility followed by hypermotility) was unaffected by pimozide. In DBA/2 mice, in which high doses of apomorphine produce hypomotility and compulsive gnawing, both these effects (but not hypomotility produced by low doses of apomorphine) were counteracted by pimozide. The results are consistent with the assumption that both strains of mice have separate inhibitory and stimulatory dopamine receptors mediating locomotor activity. In addition, DBA/2 but not C57BL/6 mice have dopamine receptors which mediate stereotypy and are sensitive to pimozide.

Animals↗
PubMed1982

Effects of dietary phospholipids and odd-chain fatty acids on the behavioural maturation of mice.

Five groups of female mice were fed from day 14 of pregnancy and throughout lactation on synthetic diets differing only in the lipid component, which constituted 10% of the diet and was derived from (a) the lipid fraction extracted from yeast grown on n-alkanes, (b) commercial soya lecithin, (c) fatty acids isolated from yeast lipids (off-chain fatty acids), (d) lipids extracted from yeast grown on glucose or (e) margarine (8%), corn oil (1%) and the unsaponifiable fraction (1%) from yeast grown on n-alkanes. A control diet (9% margarine and 1% corn oil) was fed to a sixth group of pregnant mice and to the offspring of all the groups from weaning to 60 days after birth. A battery of behavioural tests was performed on the offspring of the six groups between days 1 and 16 after birth (reflex activities), between days 2 and 21 (locomotor activity) and at 60 days of age (avoidance learning). An acceleration of postnatal behavioural maturation was evident in the pups of animals fed lipids from yeast grown on n-alkanes and of those fed soya lecithin, indicating the involvement of phospholipids and odd-chain fatty acids in the aspects of development studied.

Animals↗
PubMed1981

Cross-tolerance between D-amino acids and morphine in mice.

The effects of morphine administration on analgesia and running activity were studied in DBA/2 (DBA) and C57BL/6 (C57) mice respectively, injected with D-amino acids (D-AA) for 5 days. The results indicate a clear cross-tolerance between D-AA and morphine in DBA mice when analgesia is considered, while the stimulating effect of the opiate is not modified after D-AA pretreatment in the C57 strain.

Animals↗
PubMed1981

Behavioral effects of opiates: a pharmacogenetic analysis.

A number of studies are reviewed in relation to a pharmacogenetic approach to the effect of opiates. The behavioral effects of morphine and heroin in different species or strains of animals are considered. In particular, a number of behavioral, neurophysiological, and biochemical correlates of the opiates in different inbred strains of mice are cited. Recent studies concerning the effects of opiates on behavior have utilized the C57BL/6J and the DBA/2J strains, which are characterized by different brain levels and turnover of cholinergic and adrenergic mediators. It has been shown that the effects of opiates on running activity and on analgesia are strain-dependent, and a negative correlation is evident between the two measures in the strains considered. Experiments carried out on mice with septal lesions and on normal mice have confirmed that the motor and analgesic effects of morphine in the mouse are two distinct phenomena, which may be explained through different neurophysiological and biochemical models. Differences between the strains considered have also been observed when the ECoG response to morphine administration has been investigated. The results of these experiments have suggested: 1. The existence of a correlation between behavioral activation and sleep-like ECoG patterns. 2. The existence of a similarity between the effects of the anticholinergic drugs and those of morphine, since a dissociation between ECoG and behavior became evident following morphine administration. Some studies have also suggested that the environmental factors play an important role in determining the stimulating effects of morphine. This effect was absent in "experience" mice (i.e., in subjects already tested in the apparatus), as compared with naive "inexperienced" animals.

Animals↗
PubMed1981

Differential effects of opiate agonists-antagonists on morphine-induced hyperexcitability and analgesia in mice.

The effects of two opiate agonists-antagonists, butorphanol (4.0 and 8.0 mg/kg) and buprenorphine (0.1 and 1.0 mg/kg), were assessed on locomotor activity and analgesia in DBA/2 and C57BL/6 mice. Different behavioral effects were evident in these strains, which might be characterized by different reactions to the effects of opiates and by differences in endorphin distributions and opiate receptor populations. In particular, buprenorphine acted as an agonist-antagonist to morphine in both strains while a dissociation of butorphanol effects was evident, depending on the strain considered. The clinical implications of these findings are discussed.

Analgesia↗