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J Piasecki

Publications and source records attributed to J Piasecki.

At least 19 recordsLinked to original sources
PubMed2001

Precollisional velocity correlations in a hard-disk fluid with dissipative collisions.

Velocity correlations are studied in granular fluids, modeled by the inelastic hard sphere gas. Making a density expansion of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the evolution of the reduced distributions, we predict the presence of precollisional velocity correlations. They are created by the propagation through correlated sequences of collisions (ring events) of the velocity correlations generated after dissipative collisions. The correlations have their origin in the dissipative character of collisions, being always present in granular fluids. The correlations, that manifest microscopically as an alignment of the velocities of a colliding pair produce modifications of collisional averages, in particular, the virial pressure. The pressure shows a reduction with respect to the elastic case as a consequence of the velocity alignment. Good qualitative agreement is obtained for the comparison of the numerical evaluations of the obtained analytical expressions and molecular dynamics results that showed evidence of precollisional velocity correlations [R. Soto and M. Mareschal, Phys. Rev. E 63, 041303 (2001)].

Journal Article↗
PubMed1998

Ethanol-reinforced behaviour in the rat: effects of uncompetitive NMDA receptor antagonist, memantine.

Ethanol has been reported to alter NMDA receptor-mediated biochemical and electrophysiological responses in vitro. The aim of the present study was to evaluate the effects of an uncompetitive NMDA receptor antagonist memantine, in animal models of alcoholism. Male Wistar rats were trained to drink 8% ethanol in a free-choice, limited access procedure. A separate group of animals was trained to lever press for 8% ethanol in an operant procedure where ethanol was introduced in the presence of sucrose. The selectivity of memantine's actions was assessed by studying its effects on food or water consumption in separate control experiments. Memantine (4.5-24 mg/kg) significantly, but not dose dependently, affected ethanol drinking in the limited access procedure. However, only 6 mg/kg memantine selectively decreased ethanol drinking. Memantine did not alter ethanol intake in rats trained to lever press for ethanol in the operant procedure. Only 9 mg/kg memantine reduced operant responding in the extinction procedure in the rats trained to lever press for ethanol. The same dose of memantine significantly reduced the operant behaviour of rats trained to respond for water. These results indicate that: (i) single doses of memantine only moderately and not dose dependently reduce alcohol drinking in the limited access procedure; (ii) memantine produces non-selective effects on operant behaviour in rats trained to lever press for ethanol in an oral self-administration procedure.

Alcohol Drinking↗
PubMed1998

Prior repeated exposure to a 5-HT3 receptor agonist does not alter the ethanol-induced conditioned taste aversion in rats.

Several reports have indicated that the brain serotonergic 5-HT3 receptors are involved in at least some central effects of ethanol in rats. However, using an operant drug discrimination procedure, we have shown that these receptors are not primarily involved in the discriminative stimulus effects of ethanol. The aim of the present study was to further elucidate the role of 5-HT3 receptors in the formation of the ethanol-cueing effects in rats. To this purpose, a crossfamiliarization conditioned taste aversion (CF-CTA) procedure was used. Four daily injections of 1.5 g/kg ethanol (10% v/v) resulted in a significant attenuation of the subsequent ethanol-induced CTA. In contrast, four daily injections of the 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide (mCPBG; 50 microg per rat, i.c.v.) did not alter the subsequent ethanol-induced CTA. The 50 microg dose of mCPBG produced a marked CTA in a control experiment. These results taken together with some previous findings from our laboratory suggest that the brain 5-HT3 receptors do not play any crucial role in the mediation of the discriminative stimulus effects of ethanol.

Animals↗
PubMed1998

Studies on the role of nicotinic acetylcholine receptors in the discriminative and aversive stimulus properties of ethanol in the rat.

The role of the nicotinic acetylcholine receptor (nAChR) in the discriminative and aversive stimulus effects of ethanol was studied in rats. In the operant drug discrimination procedure the rats were trained to discriminate between 1.0 g/kg ethanol and saline under the FR10 schedule of sweetened milk reinforcement. Neither the nAChR agonist, nicotine (0.1-0.6 mg/kg) nor the nAChR antagonist, mecamylamine (3.0-6.0 mg/kg) substituted for the ethanol stimulus. Moreover, mecamylamine (0.5-6.0 mg/kg) did not antagonise the ethanol stimulus. The cross-familiarisation conditioned taste aversion procedure was used as an alternative method to study stimulus resemblance between ethanol and nicotine. Six daily injections of nicotine (0.6 mg/kg) significantly decreased a subsequent ethanol-induced taste aversion conditioning. The aversive stimulus effects of ethanol were investigated with the conditioned taste aversion (CTA) paradigm. Mecamylamine (1.0-3.0 mg/kg) did not attenuate an ethanol-induced CTA. These results suggest that: (1) nAChRs are not primarily involved in the discriminative stimulus effects of ethanol when studied with the operant drug discrimination test; (2) nAChRs are not critically involved in the ethanol-induced CTA.

Animals↗
PubMed1997

Interactions of ethanol with nicotine, dizocilpine, CGP 40116, and 1-(m-chlorophenyl)-biguanide in rats.

The present study examined the effect of ethanol (0.25-1.0 g/kg, I.P.) alone and in combination with drugs affecting different ligand-gated ion channels on a horizontal locomotor activity of male Wistar rats. None of the drugs given alone affected the locomotor activity. Similarly, combining ethanol either with nicotine (0.1 or 0.6 mg/kg, S.C.) or the competitive NMDA receptor antagonist, CGP 40116 (0.5 mg/kg, I.P.) did not result in any significant changes in ambulation. On the other hand, a significant hyperadditive interaction between ethanol (0.5 or 1.0 g/kg) and the uncompetitive NMDA receptor antagonist, dizocilpine (0.1 mg/kg, I.P.) was found. Thus, a combined administration of ethanol and dizocilpine produced a marked stimulation of the locomotor activity. Combining 1.0 g/kg ethanol with the 5-HT3 receptor agonist, 1-(m-chlorophenyl)-biguanide (5.0 mg/kg, I.P.) tended to produce locomotor stimulation. Our results suggest the existence of interaction between ethanol and the NMDA receptor complex in mediation of locomotor stimulation. Alternatively, a common neurotransmitter system (other than glutamatergic) mediate central stimulatory effects of ethanol and dizocilpine. A possible role of dopamine in this interaction is being discussed.

2-Amino-5-phosphonovalerate↗
PubMed1997

Psychiatric disorder among American Indian adolescents: prevalence in Northern Plains youth.

UNLABELLED: This article presents data on the prevalence of psychiatric disorders among American Indian adolescents, using DSM-III-R criteria. OBJECTIVE: To generate current prevalence data using a structured diagnostic instrument, the Diagnostic Interview Schedule for Children, Version 2.1C (DISC-2.1C). METHODS: Youths from a Northern Plains tribe who had participated in an earlier study comprised the sample. At reinterview, respondents were between 14 and 16 years of age, when Indian adolescents are thought to be at particularly high risk for manifesting emotional disorders. One hundred nine of the original sample of 251 were still in schools on the reservation. Trained indigenous lay interviewers administered the DISC-2.1C to respondents in a private setting within the school. RESULTS: The findings indicate that rates of some psychiatric problems (e.g., disruptive behavior disorders, substance-related disorders, and their comorbidity) are high among these high school students. CONCLUSIONS: These data, as well as national statistics, suggest that, compared with non-Indian populations, a greater percentage of Northern Plains adolescents manifest significant psychiatric symptoms which warrant treatment.

Adolescent↗
PubMed1996

Low dose of ethanol induces conditioned place preference in rats after repeated exposures to ethanol or saline injections.

Using the place conditioning paradigm (biased design), we have shown that five conditioning sessions with ethanol (0.5 or 1.0 g/kg i.p.) did not result in place conditioning response. In contrast, rats that received 20 injections of ethanol (0.5 g/kg) or saline, before the conditioning procedure, showed significant place preference to the compartment paired with 0.5 g/kg ethanol (but not 1.0 g/kg).

Animals↗
PubMed1990

[Clinical and radiological assessment of the results of using grafts of allogenic lyophilized spongy bone for filling of large postoperative jaw bone defects].

The authors describe the method of filling large bone defects in the maxilla and mandible with blocks of allogenic spongy bone enriched with biologically active substances. This method was used during 2 years in 21 cases with good results. Two-year clinical and radiological observations are reported, with detailed radiological documentation of 3 cases.

Ameloblastoma↗
PubMedDate not supplied

5-HT3 receptor antagonist, tropisetron, does not influence ethanol-induced conditioned taste aversion and conditioned place aversion.

Numerous works have demonstrated an interaction between 5-HT3 receptor antagonists and some of the effects of ethanol (EtOH) using biochemical, electrophysiological, and behavioral techniques. Thus 5-HT3 antagonists are capable of reducing EtOH-induced release of dopamine in the nucleus accumbens, EtOH-induced hyperlocomotion, and voluntary EtOH consumption in laboratory animals. In addition to its rewarding effect, EtOH possesses aversive properties as demonstrated in the conditioned taste aversion (CTA) and conditioned place aversion (CPA) paradigms. The role of 5-HT3 receptors in aversive effects of EtOH remains, however, unknown. We decided to study the effect of 5-HT3 antagonist, tropisetron, on aversive properties of EtOH (1.5 g/kg i.p.) in rats using the CTA and CPA models. In addition, effect of tropisetron on morphine (Mf)-induced CTA (10.0 mg/kg SC) was investigated. Tropisetron (0.001-0.5 mg/kg) did not influence CTA produced by EtOH and Mf. When given alone, it failed to produce any taste conditioning. Furthermore, tropisetron did not modify CPA induced by EtOH. Our results suggest that 5-HT3 receptors are not involved in aversive effects of acute doses of EtOH.

Animals↗