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Biomedical subjects

E E Zvartau

Publications and source records attributed to E E Zvartau.

At least 19 recordsLinked to original sources
PubMed2006

Co-morbidity of infectious and addictive diseases in St. Petersburg and the Leningrad Region, Russia.

The Russian health care system is organized around specific diseases, with relatively little focus on integration across specialties to address co-morbidities. This organizational structure presents new challenges in the context of the recent epidemics of injection drug use (IDU) and HIV. This paper uses existing and new data to examine the prevalence of reported new cases of drug dependence (heroin) and HIV over time as well as associations between drug dependence and alcoholism, hepatitis B and C, and tuberculosis in the City of St. Petersburg and the Leningrad region. We found a sharp rise in reported cases of IDU beginning in 1991 and continuing until 2002/2003, followed by a sharp rise in newly reported cases of HIV. These rises were followed by a drop in new cases of HIV and drug addiction in 2002/2003 and a drop in the proportion of HIV-positive individuals with IDU as a risk factor. Infection with hepatitis B and C were common, especially among injection drug users (38 and 85%, respectively), but also in alcoholics (7 and 14%). Tuberculosis was more common in alcoholics (53%) than in persons with alcoholism and drug dependence (10%), or with drug dependence alone (4%). Though these data have many limitations, they clearly demonstrate that drug dependence and/or alcoholism, HIV, hepatitis, and tuberculosis frequently co-occur in St. Petersburg and the Leningrad Region. Prevention and treatment services across medical specialties should be integrated to address the wide range of issues that are associated with these co-morbidities.

Adult↗
PubMed2004

Caffeine withdrawal syndrome in social interaction test in mice: effects of the NMDA receptor channel blockers, memantine and neramexane.

Antagonists acting at N-methyl-D-aspartate (NMDA) receptors have been demonstrated repeatedly to attenuate the expression of drug and alcohol withdrawal syndromes. The present study aimed to evaluate the effects of NMDA receptor blockade on the expression of behavioural signs of caffeine withdrawal syndrome, assessed using the social interaction paradigm. Adult male Swiss mice were treated with increasing doses of caffeine (40-100 mg/kg, i.p., twice daily) for 8 days. Twenty-four hours after the last injection of caffeine, there were significant increases in duration and frequency of defensive behaviours, as well as decreased locomotor activity. These changes faded within 72 hours. Pretreatment with a single dose of caffeine (1 mg/kg; 24 h after the end of repeated caffeine administration and 30 min prior to the test) completely reversed these withdrawal-related changes. Separate groups of mice were treated i.p. with different doses of memantine (1, 3 or 10 mg/kg) or neramexane (MRZ 2/579; 1, 3 or 10 mg/kg) 24 h after the last caffeine injection. Both compounds dose-dependently reduced the expression of defensive behaviours while increasing motor activity. These data suggest that NMDA receptor blockade may counteract the acute behavioural effects of caffeine withdrawal.

Animals↗
PubMed2003

[Pharmacotherapy in heroin addiction: pharmacological approaches to remission stabilization and recurrence prevention].

After withdrawal arrest in many heroin addicts, they displayed the syndrome of anhedonia including affective disorders (depression, dysphoria, anxiety), dyssomnia and a pathologic craving for opiates. Anhedonia is often the cause for recurrence in heroine addiction, therefore, an appropriate treatment is an important aspect in recurrence prevention and remission stabilization. Since depression and drive for heroin are the key symptoms in anhedonia, we undertook the efficiency study of therapy (in anhedonia) by antidepressants belonging to the selective serotonin reuptake inhibitors (SSRI) and NMDA receptor antagonists, citalopram and memantine, respectively, which have a clinical antidepressant action and an experimental anti-addictive action. Both drugs were found to arrest effectively virtually all signs of anhedonia, however, their action on remission stabilization was rather moderate. It looked to be more promising to use, in remission stabilization, the uttermost antagonist of opiate receptors (naltrexone) blocking reliably all heroine effects. A double blind placebo-controlled study, undertaken by us, convincingly showed a significantly smaller number of relapses with naltrexone in heroin addicts. At the same time, the drug had no valuable effect on the anhedonia symptoms, which worsened the compliance entailing a poorer therapy efficiency. Finally, a combination of naltrexone (blocking the heroin action and reducing the recurrence rate) with SSRI antidepressants (effectively arresting the anhedonia symptoms and improving the compliance with naltrexone medication and remission quality) is a most promising approach to remission stabilization and recurrence prevention.

Adult↗
PubMed2001

Opioid-NMDA receptor interactions may clarify conditioned (associative) components of opioid analgesic tolerance.

Recent evidence suggests that acute administration of opioid analgesic drugs (such as morphine or heroin) produces delayed hyperalgesia. This hyperalgesic response is likely to result from hyperactivation of NMDA receptors triggered by stimulation of opioid receptors and may mediate acute tolerance. In support of this hypothesis, blockade of NMDA receptors attenuates opioid-induced delayed hyperalgesia and prolongs the duration of antinociceptive activity of morphine. Furthermore, the NMDA receptor-induced hyperalgesia is likely an unconditioned response to opioid receptor stimulation that becomes spatiotemporally associated with environmental cues accompanying repeated opioid exposure. This hypothesis conforms to the traditional Pavlovian requirement for conditioned and unconditioned responses to be qualitatively similar. In support of the role of NMDA receptor hyperactivation in morphine tolerance, NMDA receptor antagonists have been shown to block development of analgesic tolerance induced by repeated exposures to morphine. The view of the conditioned nature of opioid tolerance may be significantly extended by assuming that upon repeated drug administration an early-onset effect of a drug may become a predictive stimulus for a later-onset effect and, consequentially, it may become empowered to elicit the later-onset effect itself. Such 'intra-drug' conditioning hypothesis is well in line with the current experimental evidence but further studies will be needed to verify it directly.

Analgesics, Opioid↗
PubMed2001

Analgesic effect of olipiphate on mouse model of chemical stimulation of peritoneum.

We studied the analgesic effect of olipiphate, a product of lignin, against writhing provoked by intraperitoneal injection of acetic acid. Paracetamol was used as the reference drug. Both agents dose-dependently decreased the number of motor reactions caused by the irritant. Olipiphate possessed analgesic activity and efficiency comparable with those of paracetamol, but produced a more long-lasting effect.

Acetic Acid↗
PubMed2001

Effects of the NMDA receptor antagonist, D-CPPene, on sensitization to the operant decrement produced by naloxone in morphine-treated rats.

Sensitization to the rate-decreasing effects of opioid antagonists induced by acute pretreatment with opioid agonists has been suggested to reflect initial changes in opioid systems that underlie physical dependence. Glutamate receptors are implicated in the development and expression of opioid dependence, and antagonists acting at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors have been shown repeatedly to attenuate the severity of opioid withdrawal. The present study evaluated the ability of a competitive NMDA receptor antagonist, D-CPPene (SDZ EAA 494; 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid), to affect morphine-induced sensitization to naloxone in rats trained to lever-press on a multiple-trial, fixed-ratio 10 schedule of food reinforcement. D-CPPene (0.3-3 mg/kg) was administered either 4 h or 30 min prior to the test session. Morphine (10 mg/kg) or its vehicle was administered 4 h before naloxone challenge (0.3-3 mg/kg). D-CPPene failed to prevent morphine-induced potentiation of the naloxone-produced decrement in operant performance. Thus, these results suggest that agonist-induced sensitization to behavioral effects of opioid antagonists may be insensitive to NMDA receptor blockade.

Animals↗
PubMed2001

Prevention of suicide by naltrexone in a recently detoxified heroin addict.

This case describes a heroin addict who was participating in a placebo-controlled randomized trial of naltrexone as an aid to relapse prevention. The patient tried to commit suicide by taking a heroin overdose after learning that he was HIV-positive. He was on naltrexone at the time and, as a result, survived what would probably have been a fatal overdose. This case demonstrates that naltrexone can have immediate as well as long-term positive effects in persons who are attempting to recover from heroin addiction.

Adult↗
PubMed2001

[Effect of marinobufagenin on the primary reinforcing effect of ethanol].

Intraperitoneal administration of marinobufagenin resulted in a reliable and dose-dependent suppression of ethanol self-administration in drug- and experimentally naive DBA/2 mice. The findings suggest that Na/K-ATPase contributes to both mediation of the ethanol reinforcing properties and the mood regulation.

Alcohol Drinking↗
PubMed2000

Effects of NMDA receptor antagonists on cocaine-conditioned motor activity in rats.

NMDA receptor antagonists have been reported to affect learned behaviors conditioned with abused drugs, with the outcome dependent, in part, on the class of NMDA receptor antagonist used. The present study tested the ability of various site-selective NMDA receptor antagonists to modify cocaine-conditioned motor activity. Two procedures were used for independently assessing drug effects on spontaneous activity and expression of cocaine-conditioned behavior. In the conditioning experiments, rats were administered i.p. injections of cocaine (30 mg/kg) or saline paired with distinctive environments. Spontaneous horizontal activity was dose-dependently enhanced by dizocilpine (0.03-0.3 mg/kg) and memantine (1-30 mg/kg), but not by D-CPPene (3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid; SDZ EAA 494; 1-10 mg/kg), ACEA-1021 (5-nitro-6,7-dichloro-1,4-dihydro-2, 3-quinoxalinedione; 3-56 mg/kg), or eliprodil (3-30 mg/kg). Higher doses of memantine, D-CPPene (1-10 mg/kg), eliprodil (3-30 mg/kg), or ACEA-1021 reduced vertical activity. Following five cocaine-environment pairings, rats displayed significant increases in motor activity when exposed to the cocaine-paired environment. The following antagonists were administered prior to the conditioning test: dizocilpine (MK-801; 0.03-0.1 mg/kg), memantine (1-10 mg/kg), D-CPPene (0.3-3 mg/kg), ACEA-1021 (3-10 mg/kg), and eliprodil (1-10 mg/kg). Of these, memantine, ACEA-1021 and, to the lesser degree, eliprodil attenuated expression of cocaine-conditioned motor activity at doses that did not significantly affect spontaneous motor activity. These results show that cocaine-conditioned behaviors can be selectively modulated by some, but not all, NMDA receptor antagonists.

Animals↗
PubMed2000

Decrement in operant performance produced by NMDA receptor antagonists in the rat: tolerance and cross-tolerance.

Current perspectives on the clinical use of NMDA receptor antagonists infer repeated administration schedules for the management of different pathological states. The development of tolerance and cross-tolerance between different NMDA receptor antagonists may be an important factor contributing to the clinical efficacy of these drugs. The present study aimed to characterize the development of tolerance and cross-tolerance to the ability of various site-selective NMDA receptor antagonists to produce a decrement of operant responding (multiple extinction 9 s fixed-interval 1-s schedule of water reinforcement). Acute administration of D-CPPen (SDZ EAA 494; 1-5.6 mg/kg), dizocilpine (MK-801; 0.03-0.3 mg/kg), memantine (0.3-17 mg/kg), ACEA-1021 (10-56 mg/kg), and eliprodil (1-30 mg/kg) differentially affected operant responding. Both increases and decreases in response rates and accuracy of responding were observed. Repeated preexposure to D-CPPen (5.6 mg/kg, once a day for 7 days) attenuated a behavioral disruption produced by an acute challenge with D-CPPen or ACEA-1021, but potentiated the effects of dizocilpine, memantine, and eliprodil. Based on the present results, one can suggest that the repeated administration of a competitive NMDA receptor antagonist differentially affects the functional activity of various sites on NMDA receptor complex.

Animals↗
PubMed2000

Influence of buprenorphine, butorphanol and nalbuphine on the initiation of intravenous cocaine self-administration in drug naive mice.

The influence of different mixed mu-kappa-opioid receptor agonists-antagonists on cocaine reinforcement was studied using the method of initiation of intravenous cocaine self-administration in naive mice. Self-administration of cocaine was readily initiated according to an inverted U-shaped unit dose-response curve. Buprenorphine, butorphanol and nalbuphine tested against the optimal unit dose of cocaine (0.8 microg per infusion), inhibited initiation of cocaine self-administration in a dose-dependent manner. When tested against a scale of cocaine unit doses (0.2 -1.6 microg per infusion) buprenorphine (0.1 mg/kg, s.c.) and nalbuphine (2 mg/kg, s. c.) produced a shift of the optimal cocaine dose from 0.8 to 0.4 microg/inf, while butorphanol (1 mg/kg, s.c.) shifted the optimal unit dose of cocaine to the right along the cocaine unit doses axis. Co-administration of naloxone (0.1 mg/kg, s.c.) significantly reduced the effect of buprenorphine but failed to influence the effect of nalbuphine and butorphanol on cocaine intake. Taken together, these results suggest that nalbuphine is capable of affecting cocaine's reinforcing properties in the same manner as buprenorphine during the initiation phase of cocaine self-administration behavior, while butorphanol causes the opposite effect. Although the exact opioid profile of action of the mixed opioid receptor agonists-antagonists is as yet not precisely known, the present findings suggest that multiple opioid receptor systems (i.e. mu and kappa) play a role in reinforcing properties of cocaine and that a co-operative interaction between mu- and kappa-opioid systems may be of importance during initiation of cocaine self-administration.

Analysis of Variance↗
PubMed2000

Effects of N-methyl-D-aspartate receptor antagonists on reinstatement of cocaine-seeking behavior by priming injections of cocaine or exposures to cocaine-associated cues in rats.

The reinstatement of extinguished cocaine self-administration behavior was studied in rats pretreated with N-methyl-D-aspartate receptor antagonists. Rats were trained to self-administer intravenous cocaine (0.32 mg/kg/infusion) during five consecutive daily sessions that were followed by five consecutive daily extinction sessions, during which cocaine was unavailable and cocaine-associated cues (sound and light) were absent. Neither the competitive N-methyl-D-aspartate receptor antagonist D-CPPene (0.3-3 mg/kg) nor the low-affinity N-methyl-D-aspartate receptor channel blocker memantine (1-10 mg/kg) reinstated extinguished responding. Priming injections of intravenous cocaine (Experiment 1), and exposures to cocaine-associated stimuli (buzzer and light; Experiment 2) engendered responding on the reinforced lever in excess of that on the non-reinforced lever. In Experiment 1, administration of D-CPPene or memantine prior to the priming injection of cocaine eliminated the difference between reinforced-lever and non-reinforced-lever response rates. For both D-CPPene and memantine, however, this effect was largely due to increased responding upon the non-reinforced lever rather than to decreased reinforced-lever responding. In Experiment 2, D-CPPene, but not memantine, abolished in a dose-dependent manner the selective increase in reinforced-lever over non-reinforced-lever responding that was induced by exposures to cocaine-related stimuli. This effect of D-CPPene was not due to increased non-reinforced-lever responding. These data help define the boundaries within which N-methyl-D-aspartate receptor antagonists can prevent reinstatement of cocaine-seeking behavior (e.g. type of antagonist used and reinstatement procedure).

Animals↗
PubMed1999

Involvement of endogenous digitalis-like factors in voluntary selection of alcohol by rats.

This study tested the hypothesis that endogenous digitalis-like factor (DLF) is involved in the development of alcohol dependence in rats. In 33 male Wistar rats in conditioned place preference (CPP) experiment, ethanol evoked increase in time spent in the ethanol-associated compartment (702+/-82 in ethanol-treated vs. 426+/-86 sec in the controls). Digoxin pretreatment (125 microg/kg, i/p) did not affect the time spent in the water-associated compartment (476+/-80 sec), but prevented the acquisition of ethanol CPP (385+/-112 sec in ethanol-paired side, P<0.05). In a two bottle choice test, where rats (n=6 per group) chose between drinking water and 9% ethanol, immunization against two putative DLFs, marinobufagenin and ouabain (MBG and OLC) resulted in a 60% increase of ethanol consumption. Acute intragastric administration of 9% ethanol to the rats was associated with increased OLC in cerebrospinal fluid, and stimulated urinary excretion of MBG and OLC. Thus, in rats, digoxin, which mimics the effects of DLFs, suppresses the free choice of alcohol, while immunization against DLFs is associated with alcohol seeking behavior.

Alcohol Drinking↗
PubMed1999

Caffeine, acting on adenosine A(1) receptors, prevents the extinction of cocaine-seeking behavior in mice.

Drug-naive DBA/2 mice were trained to self-administer cocaine (40 microgram/kg/infusion) i.v. by nose poking. The number of nose-poke responses was higher in mice receiving response-contingent injections of cocaine (active group) than in yoked controls or in animals receiving response-contingent saline injections. Twenty-four hours after the training session (cocaine or saline self-administration), mice were injected i.p. with saline, cocaine, caffeine, 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX), 8-cyclopentyl theophylline (8-CPT), 5-amino-7-(2-phenylethyl)2-(2-furyl)-pyrazolo-[4,3-e]-1,2, 4-triazolo[1,5-c]pyrimidine (SCH 58261), or 9-chloro-2(2-furyl)[1,2, 4]triazolo[1,5-c]quinazolin-5-amine (CGS 15943) and placed again in exactly the same operant boxes as during the training session but without response-contingent i.v. infusions. Saline injection elicited similar responding in animals from the active group and from the yoked control group. A low dose of cocaine (5 mg/kg) or caffeine (3 mg/kg), but not higher doses, produced greater responding in the active group than in the yoked control group during a single extinction trial. The adenosine A(1)-receptor antagonists DPCPX and 8-CPT and the nonselective antagonist CGS 15943 partially reproduced the effect of a low dose of caffeine on the cocaine-associated behavior in a dose-dependent manner and did not alter the nose-poke activity of yoked control mice in the extinction experiment. In contrast, the adenosine A(2A) antagonist SCH 58261, in doses above 1 mg/kg, reduced nose-poke activity equally in active and yoked control animals. This confirms that a drug from a different pharmacological class (adenosine-receptor antagonist) can induce behavior changes similar to the effects of the original self-administered drug (indirect dopamine-receptor agonist). The data also suggest that the effects of caffeine on cocaine-seeking behavior might be related to interaction with adenosine A(1) receptors, but not A(2A) receptors.

Animals↗
PubMed1998

Caffeine place conditioning in rats: comparison with cocaine and ethanol.

The present study employed the place conditioning technique to compare rewarding potential of caffeine with that of cocaine and ethanol. In Experiment 1 caffeine, cocaine and ethanol place conditioning were estimated independently, whereas in Experiments 2 and 3 the preference of the external cues associated with caffeine vs. cocaine and caffeine vs. ethanol was assessed in a single test. Caffeine (1.5 mg/kg, i.p.) cocaine (5 mg/kg, i.p.) and ethanol (1.2 g/kg, i.g.) did produce secondary reinforcing effects comparable in magnitude (Experiment 1). In Experiments 2 and 3 animals had the opportunity 'to compare' rewarding effects of two drugs. Data showed that the preference of cocaine-paired cues was absolutely (100%) higher than those of caffeine, whereas reinforcing actions of caffeine and ethanol seemed to be equal. The proposed modification of conditioned place preference procedure may be useful for the comparison of rewarding values of different drugs with presumed addictive potential.

Analysis of Variance↗
PubMed1998

[Co-housing in the group with stable hierarchy is not aversive for dominant and subordinate animals].

Behaviour of individuals and their responses to external stimuli are controlled by the micro-social environment in which most mammals are subject to dominant-subordinate relations. Physiological (pain sensitivity, immunological data: thymus and spleen weight, first immunological response) and behavioural (locomotor activity, shuttle-box behaviour) signs were studied in dominant and subordinate male mice of linear hierarchy groups. No significant difference was found between both groups of sings in both groups of the animals. Housing of dominant with subordinate mice seems not to be aversive for both types of the animals.

Aggression↗