Differential effects of cocaine and dopaminergic agonists on hypokinesia induced by dopaminergic antagonists

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

Pharmacological characterization of the enhancement of apomorphine-induced gnawing in mice by cocaine

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 ▲]

Behavioral and pharmacological differentiation of direct and indirect dopamine agonists and among dopamine uptake inhibitors

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

Gnawing induced by dopaminergic mobilzation : differential effects of direct and indirect dopamine agonists in mice

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

Verticalization of behavior elicited by dopaminergic mobilization is qualitatively different between C57BL/6J and DBA/2J mice

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 ▲]

Behavioral sensitization and tolerance to the D-sub-2 agonist RU 24213 : dissociation between several patterns in mice

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

Oxytocin blocks the environmentally conditioned compensatory response present after tolerance to ethanol-induced hypothermia in mice

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 ▲]

Oxytocin attenuates tolerance not only to the hypothermic but also to the myorelaxant and akinesic effects of ethanol in mice

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 ▲]

Adult-like neurobehavioral changes induced by a GABA-A agonist in infant and weanling mice

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

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 ▼]

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 Exp 1, relatively high doses of muscimol (0.05-0.40 mg/kg in developing and 0.50-3 mg/kg in adult Ss) were found to dose-dependently induce solid catalepsy and ataxia. In Exp 2, the GABA agonist was injected in dose ranges that included relatively small concentrations to assess its excitatory properties, observable in adults, on rearing and locomotion in developing mice. Levels of rearing and especially locomotion were enhanced at low doses (0.025-0.050 mg/kg in developing and 1.3-2.9 mg/kg in adult mice) and inhibited at higher ones (0.150 mg/kg in developing and 1.9 and 2.5 mg/kg in adult mice). ((c) 1997 APA/PsycINFO, all rights reserved) [less ▲]

The GANA-A agonist muscimol facilitates muscular twitches and locomotor movements in the neonatal mouse

in Pharmacology, Biochemistry & Behavior (1990), 33