References of "Tirelli, Ezio"
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See detailNeonatal and Preweanling Rats Are Able to Express Short-Term Behavioral Sensitization to Cocaine
Tirelli, Ezio ULg; Ferrara, Marie-Antoinette ULg

in European Journal of Pharmacology (1997), 328(2-3), 103-14

The present study assessed the ability of suckling rats to express short-term behavioral sensitization to cocaine prior to weaning. Rat pups, aged either 3, 5, 10, 12, 17 or 19 days at the beginning of ... [more ▼]

The present study assessed the ability of suckling rats to express short-term behavioral sensitization to cocaine prior to weaning. Rat pups, aged either 3, 5, 10, 12, 17 or 19 days at the beginning of the experiment, were placed in a chamber after daily injection with cocaine (7.5 or 15 mg/kg. i.p.) for either 2 or 4 consecutive days, and were tested for behavioral responsiveness to cocaine in the same chamber 24 h later (at either 7, 14 or 21 days of age). Such a short post-treatment interval was adopted, along with a consistent pairing of the testing context with the drug effect and a sensitive technique of behavioral measurement (video recording), in order to maximize the possibility of detecting any cocaine sensitization. Locomotion was sensitized at all ages, after both regimens in 14-day-old pups, but solely after 2 injections in 21- and 4 injections in 7-day-old pups. Sensitization was also expressed via behaviors specific to each age. Four cocaine injections augmented cocaine-induced uncoordinated movements of head, paws and body (horizontal activity) in 7-day-old pups, and mouth movements in 14-day-old pups. In 21-day-old pups, sensitization was dose- and regimen-dependently expressed via adult-like stereotyped head movements. In neonatal 7-day-old pups, cocaine sensitization was also visible as reductions in immobility (both injection regimens). Contrary to previous studies, these results indicate that, given the use of an appropriate methodology, short-term sensitization to the motoric effects of cocaine can be expressed by suckling rats prior to weaning, even after relatively short regimens of daily injections. [less ▲]

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See detailDopamine 'D2-like' receptor agonists in combination with cocaine: absence of interactive effects on locomotor activity.
Tirelli, Ezio ULg; Reggers, Jean ULg; Terry, P.

in Behavioural Pharmacology (1997), 8(2-3), 147-59

This study examined interactions between cocaine and drugs that act as direct agonists at subtypes of "D2-like" dopamine receptors. The drugs 7-OH-DPAT, quinpirole and RU24213 were studied alone and in ... [more ▼]

This study examined interactions between cocaine and drugs that act as direct agonists at subtypes of "D2-like" dopamine receptors. The drugs 7-OH-DPAT, quinpirole and RU24213 were studied alone and in combination with cocaine for their effects on locomotor activity in non-habituated mice. Locomotor activity was measured by photobeam crossings over 140 min. At the doses given (7-OH-DPAT: 0.006-6.4 mg/kg; quinpirole: 0.001-1 mg/kg; RU24213: 0.008-8 mg/kg) all three direct agonists dose-dependently reduced locomotor activity throughout the test, whereas cocaine (0.6-20 mg/kg) produced dose-related hyperactivity. Next, for each direct agonist, a series of doses was selected (up to threshold behaviourally-active doses) as pretreatments to a sub-maximally stimulant dose of cocaine (15 mg/kg). 7-OH-DPAT and quinpirole did not modulate the effects of cocaine; RU24213 produced, at best, a very modest attenuation of the effects of cocaine. Finally, a series of cocaine doses (below stimulant threshold) was given before a single dose of each direct agonist (the lowest dose to reduce activity significantly). Cocaine did not reliably alter the hypoactivity produced by any of the D2-like agonists. By demonstrating negligible interactions between cocaine and D2-like agonists, the results fail to demonstrate any necessary involvement of D2-like receptors in one of the behavioural effects of cocaine. [less ▲]

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See detailBehavioral cross-sensitization between quinpirole and preweaning rats.
Tirelli, Ezio ULg; Schoonbroodt, Roland

in Society for Neuroscience Abstracts (1996), 22

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See detailDifferential effects of cocaine and dopaminergic agonists on hypokinesia induced by dopaminergic antagonists
Terry, P.; Tirelli, Ezio ULg

in National Institute on Drug Abuse Research Monograph Series (1996), 142

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See detailOntogenetic aspects of individual differences in behavioral responsiveness to cocaine in rats
Michel, Alexa ULg; Tirelli, Ezio ULg

in Behavioural Pharmacology (1996), 10(Suppl.), 211-212

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See detailPharmacological characterization of the enhancement of apomorphine-induced gnawing in mice by cocaine
Tirelli, Ezio ULg; Witkin, J. M.

in Pharmacology, Biochemistry & Behavior (1996), 55(1), 135-140

Characterized the behavioral and pharmacological mechanisms associated with cocaine potentiation of apomorphine (AP)-induced gnawing (AIG) in male C57BL/6J mice. Results showed that (-)-cocaine enhanced ... [more ▼]

Characterized the behavioral and pharmacological mechanisms associated with cocaine potentiation of apomorphine (AP)-induced gnawing (AIG) in male C57BL/6J mice. Results showed that (-)-cocaine enhanced AIG at doses devoid of effects on gnawing when given alone; (+)-cocaine or (-)-cocaine methiodide were also devoid of effects. Lidocaine, a local anesthetic without prominent dopaminergic actions, augmented the gnawing response to AP without increasing climbing or gnawing when given alone. (+)-Amphetamine enhanced AIG gnawing but only at a high dose that increased gnawing by itself. The selective dopamine (DA) uptake blocker, GBR 12909, augmented AIG by itself; however, it increased climbing at doses that augmented the gnawing response. These data indicate that the cocaine-augmented gnawing response to AP may be due to blockade of DA uptake and or the local anesthetic actions of cocaine. ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

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See detailInvolvement of the GABA-A sites in the inhibitive effects of nicotine on individual behaviors in mice
Mancuso, G.; Tirelli, Ezio ULg

in Pflügers Archiv : European Journal of Physiology (1995), 333

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See detailBehavioral and pharmacological differentiation of direct and indirect dopamine agonists and among dopamine uptake inhibitors
Witkin, J. M.; Tirelli, Ezio ULg; Geter-Douglass, B.

in National Institute on Drug Abuse Research Monograph Series (1995), 131

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See detailDifferential effects of drawing and indirect dopamine agonists on the induction of gnawing in C57BI/6J mice
Tirelli, Ezio ULg; Witkin, J. M.

in Journal of Pharmacology and Experimental Therapeutics (The) (1995), 273(1), 7-15

Compared the ability of indirect dopamine (DA) agonists to induce gnawing behavior (GB) in male C57BL/6J mice with that of direct DA agonists acting at DA D-sub-1 or D-sub-2 receptor subtypes. Eight Ss ... [more ▼]

Compared the ability of indirect dopamine (DA) agonists to induce gnawing behavior (GB) in male C57BL/6J mice with that of direct DA agonists acting at DA D-sub-1 or D-sub-2 receptor subtypes. Eight Ss were used per dose. Holes left by Ss on corrugations of packing cardboard were used as an objective index of GB. Indirect DA agonists, including DA releasers such as fencamfamine and amfonelic acid and DA uptake inhibitors such as cocaine and nomifensine, produced dose-dependent increases in GB. None of the direct agonists (e.g., apomorphine, quinpirole) increased GB. The dopaminergic nature of GB was confirmed in studies in which a host of compounds (e.g., nicotine, caffeine, dizocilpine) with primary actions at nondopaminergic sites did not induce GB. Given the general contrast between the effects of direct and indirect DA agonists, this procedure could serve as a rapid in vivo method of distinguishing direct- from indirect-acting DA agonists. ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

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See detailGnawing induced by dopaminergic mobilzation : differential effects of direct and indirect dopamine agonists in mice
Tirelli, Ezio ULg; Witkin, J. M.

in Journal of Pharmacology and Experimental Therapeutics (The) (1995), 273

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See detailEarly ontogenesis od sensitization to the behavioral effects of cocaine in rats.
Tirelli, Ezio ULg; Adam, Eric; Ferrara, Maurizio

in Behavioural Pharmacology (1994), 5

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See detailVerticalization of behavior elicited by dopaminergic mobilization is qualitatively different between C57BL/6J and DBA/2J mice
Tirelli, Ezio ULg; Witkin, J. M.

in Psychopharmacology (1994), 116(2), 191-200

Behavioral effects of dopaminergic stimulation were compared for C57BL/6J mice and DBA/2J mice. Effects of apomorphine (APO) alone and in combination with cocaine (COC) were assessed using a time-sampling ... [more ▼]

Behavioral effects of dopaminergic stimulation were compared for C57BL/6J mice and DBA/2J mice. Effects of apomorphine (APO) alone and in combination with cocaine (COC) were assessed using a time-sampling technique that classified climbing and leaning in separate categories. Climbing occurred in DBA/2J mice only at doses of APO that were 16 times higher than the smallest effective dose in C57BL/6J mice, but relative to baseline values, effects were comparable. Whereas DBA/2J mice showed dose-dependent leaning under APO, C57BL/6J mice exhibited significantly increased leaning only after the highest APO dose. When given alone, COC produced significant climbing, but not leaning or gnawing, in either strain. COC potentiated APO-induced climbing and gnawing in both strains but did not consistently change APO-induced leaning in either strain. APO alone reduced locomotor activity and attenuated COC-induced hyperkinesia. ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

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See detailTransient hypersensitivity to apomorphine-induced gnawing after termination of acute effects high dose of cocaine
Tirelli, Ezio ULg; Witkin, J. M.

in Behavioural Pharmacology (1994), 5(3), 289-298

Male mice were tested for behavioral effects (BEs) of the dopamine (DA) agonist apomorphine (AP) at various times after acute administration of cocaine (COC). When most of the COC had disappeared from ... [more ▼]

Male mice were tested for behavioral effects (BEs) of the dopamine (DA) agonist apomorphine (AP) at various times after acute administration of cocaine (COC). When most of the COC had disappeared from brain and the BEs of COC had dissipated (2 hrs and 4 hrs after administration), effects of AP on gnawing were increased 4-fold. This dopaminergic hypersensitivity (DA-H) was induced by acute treatment with doses of 15 mg/kg COC and higher. Effects of AP were not enhanced 6-24 hrs after COC, indicating a rapid waning of the DA-H. Hypersensitivity to AP (AP-H) was not further augmented by 8 days of daily COC injections. COC did not influence climbing and hypomotility induced by AP 4 hrs after its injection, demonstrating selectivity in the BEs of the DA-H. Further, COC did not induce sensitization to its own effects, indicating that the AP-H was not due to a typical sensitization phenomenon. ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

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See detailBehavioral sensitization and tolerance to the D-sub-2 agonist RU 24213 : dissociation between several patterns in mice
Tirelli, Ezio ULg; Jodogne, C.

in Pharmacology, Biochemistry & Behavior (1993), 44(3), 627-632

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See detailBiphasic locomotor effects of the dopamine D-sub-1 agonist SKF 38393 and their attenuation in non-habituated mice
Tirelli, Ezio ULg; Terry, P.

in Psychopharmacology (1993), 110(1-2), 69-75

Examined the locomotor stimulatory effects of the dopamine D-sub-1 receptor partial agonist SKF 38393 in male C57B1/6J mice. Non-habituated mice showed marked dose-related (3-300 mg/kg, subcutaneously ... [more ▼]

Examined the locomotor stimulatory effects of the dopamine D-sub-1 receptor partial agonist SKF 38393 in male C57B1/6J mice. Non-habituated mice showed marked dose-related (3-300 mg/kg, subcutaneously) locomotor stimulation. The time-course effect was biphasic at very high doses (100-300 mg/kg), with dose-related locomotor depression followed by dose-related long-term hyperlocomotion. For all doses, locomotor effects were detectable throughout the 4-hr test period. To determine whether these effects were mediated by D-sub-1 receptor stimulation, effects of SKF 38393 were assessed in combination with behaviorally inactive and active doses (0.1 and 0.2 mg/kg, respectively) of the selective D-sub-1 receptor antagonist SCH 39166. Both doses of SCH 39166 attenuated the hyperlocomotion induced by 30 mg/kg of the agonist to a similar degree. However, neither dose was able to reverse either the depressant or the stimulatory effects of 300 mg/kg SKF 38393. ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

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See detailOxytocin blocks the environmentally conditioned compensatory response present after tolerance to ethanol-induced hypothermia in mice
Tirelli, Ezio ULg; Jodogne, C.; Legros, Jean-Jacques ULg

in Pharmacology, Biochemistry & Behavior (1992), 43(4), 1263-1267

The present study tested the hypothesis that the attenuation by oxytocin of tolerance to ethanol-induced hypothermia relies upon an impairment of the putative conditioning processes underlying environment ... [more ▼]

The present study tested the hypothesis that the attenuation by oxytocin of tolerance to ethanol-induced hypothermia relies upon an impairment of the putative conditioning processes underlying environment-specific tolerance. According to the conditioning model of tolerance, such tolerance occurs because an opposite compensatory response conditioned to ethanol-paired cues attenuates ethanol's effects. Tolerance to ethanol-induced hypothermia was established to a particular environment over 4 days by injecting mice (daily) with oxytocin 2 h before ethanol, outside the colony room. As controls, other mice were injected similarly but following testing in the animal room. We found that oxytocin suppressed the conditioned compensatory response, revealed by injecting saline to every group in the tolerance-associated environment. These results suggest that oxytocin acted, at least partly, via an inhibition of the associative learning processes that facilitate tolerance development. [less ▲]

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See detailConditioned amphetamine effects and habituation in mice
Tirelli, Ezio ULg; Terry, P.

in National Institute on Drug Abuse Research Monograph Series (1992), 119

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See detailOxytocin attenuates tolerance not only to the hypothermic but also to the myorelaxant and akinesic effects of ethanol in mice
Jodogne, C.; Tirelli, Ezio ULg; Klingbiel, P. et al

in Pharmacology, Biochemistry & Behavior (1991), 40(2), 261-265

Inhibition of ethanol tolerance by oxytocin has been demonstrated previously using the hypothermic effect only. The purpose of the present experiment was to investigate the effect of oxytocin on the ... [more ▼]

Inhibition of ethanol tolerance by oxytocin has been demonstrated previously using the hypothermic effect only. The purpose of the present experiment was to investigate the effect of oxytocin on the development of tolerance to ethanol-induced hypothermia, myorelaxation and akinesia in mice. Four groups of mice received daily intraperitoneal injections of saline or oxytocin (0.005 mg) plus saline or ethanol (2 g/kg). The peptide was administered 2 hours before ethanol. For five consecutive days, temperature measurements were performed 20 minutes before and after ethanol injection. Myorelaxation and akinesia were evaluated following the second temperature measure. Oxytocin pretreatment, which had no intrinsic effects, resulted in a robust selective attenuation of tolerance to ethanol-induced hypothermia, myorelaxation and akinesia. These results suggest that the mechanisms for peptide modulation are common to these three typical effects of ethanol. [less ▲]

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See detailAdult-like biphasic neurobehavioral changes induced by a GABA-A agonist in infant and weanling mice
Tirelli, Ezio ULg; Jodogne, C.; Perikel, J. J.

in Brain Research. Developmental Brain Research (1991), 61(2), 207-215

The neurobehavioral responsivity to peripherally injected muscimol, a gamma-aminobutyric acid-A (GABA-A) agonist, was assessed in infant (14-day-old), weanling (20-day-old) and young adult (53-day-old ... [more ▼]

The neurobehavioral responsivity to peripherally injected muscimol, a gamma-aminobutyric acid-A (GABA-A) agonist, was assessed in infant (14-day-old), weanling (20-day-old) and young adult (53-day-old) outbred male mice. In the first experiment, relatively high doses of muscimol (ranging from 0.05 to 0.40 mg/kg in developing and from 0.50 to 3 mg/kg in adult animals) were found to dose-dependently induced solid catalepsy and ataxia, evaluated 5 times at 20-min intervals. In the second experiment, the GABA agonist was injected in dose ranges which include relatively small concentrations in order to assess its excitatory properties, observable in adults, on rearing and locomotion in developing mice. It appeared that levels of rearing and especially locomotion were enhanced at the low doses (0.025 and 0.050 mg/kg in developing, and 1.3 and 1.9 mg/kg in adult mice) and inhibited at the higher ones (0.150 mg/kg in developing and 1.9 and 2.5 mg/kg in adult mice). This adult-like biphasic action of muscimol in developing mice--excitation at low and depression/sedation at high doses--strongly suggests a full maturation of the GABA-A-related behavioral functions at a period of ontogeny where adult-like locomotion emerges. Given that previous studies have shown that muscimol can biphasically affect behavioral activity in newborn murines as well, it is suggested that GABA-related behavioral functions mature near-monotonically during ontogeny, unlike those related to other major neurotransmitter systems. [less ▲]

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