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Biomedical subjects

M V Pletnikov

Publications and source records attributed to M V Pletnikov.

18 recordsLinked to original sources
PubMed2001

Neonatal Borna disease virus infection (BDV)-induced damage to the cerebellum is associated with sensorimotor deficits in developing Lewis rats.

Neonatal Borna disease virus (BDV) infection of the brain produces developmental damage to the cerebellum in Lewis rats, with minimal classical inflammatory responses. In the present study, we assessed the consequences of this damage by measuring motor coordination and postural skills in developing (postnatal days 4 to 30) Lewis rats that were neonatally infected with BDV. Neonatal BDV infection-induced motor impairments were selective and correlated with the time course of BDV damage to cerebellar development. BDV-induced motor deficits were not seen until the end of postnatal week 2. By postnatal week 3, BDV-infected rats had deficits in negative geotropism, fore- and hind limb placing and grasping. BDV-infected rats also exhibited deficits in the ability to hold on to a bar and to cross a suspended bar. Neonatal BDV infection induced impairments in the acoustic startle response. Compared to controls, neonatally BDV-infected rats exhibited attenuated habituation of the acoustic startle at postnatal day (PND) 23 and decreased startle responsiveness at PND 30. Prepulse inhibition of the acoustic startle remained unaltered in BDV-infected rats. The data demonstrate that neonatal BDV brain infection of rats can be a valuable animal model system for studying the relationship between abnormal brain development and resultant behavioral deficits. Further studies of this model may elucidate specific pathogenic mechanisms that that may have implications in the study of neurodevelopmental human disorders.

Animals↗
PubMed2001

Borna disease: virus-induced neurobehavioral disease pathogenesis.

Studies of the pathogenesis of neurobehavioral diseases following Borna disease virus infections have been increasing rapidly over the past ten years. Recent major advances have included a report of vertical transmission of the virus in its natural host, the horse, and a report of isolation of a novel variant, No/98, in that same species. In rats infected neonatally with the Borna disease virus that lack blood-borne inflammation in the brain, evidence of an "endogenous" brain inflammatory response is abundant, with elevated expression of cytokine and chemokine mRNA. Infection in these rats is also associated with abnormal levels of neurotransmitters, including serotonin and norepinephrine. Data and debate continue to be forthcoming about the role of Borna disease virus in human infection and psychiatric disease.

Animals↗
PubMed2000

Effects of neonatal rat Borna disease virus (BDV) infection on the postnatal development of the brain monoaminergic systems.

Effects of neonatal Borna disease virus infection (BDV) on the postnatal development of brain monoaminergic systems in rats were studied. Tissue content of norepinephrine (NE), dopamine (DA) and its metabolite, 3,4-dihydroxyphenol acetic acid (DOPAC), and serotonin (5-HT) and its metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) were assayed by means of HPLC-EC in frontal cortex, cerebellum, hippocampus, hypothalamus and striatum of neonatally BDV-infected and sham-inoculated male Lewis rats of 8, 14, 21, 60 and 90 days of age. Both NE and 5-HT concentrations were significantly affected by neonatal BDV infection. The cortical and cerebellar levels of NE and 5-HT were significantly greater in BDV-infected rats than control animals at postnatal days (PND) 60 and 90. Tissue content of NE in hippocampus was unaffected. In hippocampus, neonatally BDV-infected rats had lower 5-HT levels at PND 8 and significantly elevated levels at PND 21 and onwards. Neither striatal levels of 5-HT nor hypothalamic levels of 5-HT and NE were affected by neonatal BDV infection, suggesting that the monoamine systems in the prenatally maturing brain regions are less sensitive to effects of neonatal viral infection. 5-HIAA/5-HT ratio was not altered in BDV-infected rats indicating no changes in the 5-HT turnover in the brain regions damaged by the virus. Neither DA nor DOPAC/DA ratio was affected by neonatal BDV infection in any of the brain regions examined. The present data demonstrate significant and specific alterations in monoaminergic systems in neonatally BDV-infected rats. This pattern of changes is consistent with the previously reported behavioral abnormalities resulting from neonatal BDV infection.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1999

Persistent neonatal Borna disease virus (BDV) infection of the brain causes chronic emotional abnormalities in adult rats.

Neonatal Borna disease virus (BDV) brain infection results in selective developmental damage to the hippocampal dentate gyrus and the cerebellum. When mature, neonatally BDV-infected rats show extreme locomotor hyperactivity and reduced freezing behavior in novel environments. Traditional interpretation of both of these behavioral abnormalities would suggest decreased anxiety in infected rats compared to normal animals. However, it also possible that the locomotor hyperactivity in infected rats reflects higher rather than reduced anxiety, and is the result of increased escape responses to aversive stimuli. The present experiments were undertaken to test a hypothesis about elevated anxiety in neonatally BDV-infected adult Lewis rats by studying their species-specific fear-related responses. Compared to normal subjects, BDV-infected rats exhibited locomotor hyperactivity and elevated defecation in a highly aversive, brightly lit open field. As expected, in a less aversive, dimly lit open field, uninfected controls increased ambulation, whereas infected rats significantly decreased locomotor activity and defecation. Unlike uninfected rats, BDV-infected rats exhibited an attenuated freezing response immediately after loud auditory stimuli. On the contrary, immediate freezing responses following footshock were comparable in the two groups of animals indicating an intact ability to freeze in BDV-infected rats. Despite a decreased baseline startle responsiveness, BDV-infected rats demonstrated increased sensitization of the startle response by preceding footshocks, suggesting a tendency toward elevated escape responses. Compared to normal subjects, BDV-infected rats showed decreased conditional freezing and elevated conditional defecation response in the context previously paired with aversive stimulation indicating sparing of an autonomic component of fear conditioning. The findings indicate that neonatally BDV-infected adult rats are hyperreactive to aversive stimuli, possibly as a result of chronic emotional abnormalities.

Affective Symptoms↗
PubMed1999

Developmental brain injury associated with abnormal play behavior in neonatally Borna disease virus-infected Lewis rats: a model of autism.

Play behavior, nonsocial exploratory activity, and nonplay social interaction were observed in male juvenile Lewis rats with brain developmental injury following neonatal infection with Borna disease virus (BDV). These behaviors were tested using the 'intruder-resident' paradigm, with social isolation of residents for six days prior to testing. Four experimental pairings of infected (BDV) and uninfected (NL) rats were studied as follows: NL-NL; NL BDV; BDV NL; and BDV-BDV (the first member is the resident, the second member is the intruder). Observation of social activities was carried out for 10 min on two consecutive days. Nonsocial exploratory activity (e.g. ambulation and rearing) was similar in BDV and NL residents. Duration of nonplay social investigation (e.g. sniffing, approach, and follow) was higher in BDV residents as compared to NL residents when tested on the first test day. On the second day, all rats showed similar level of nonplay social interaction. When confronted with NL intruders, NL residents exhibited significantly more play behavior compared to the NL-BDV, BDV NL and BDV-BDV pairs, when play behavior was measured by the number of 'pins'. Moreover, irrespective of a type of intruder, NL residents demonstrated higher play soliciting behavior than BDV residents, indicating attenuated readiness to play in BDV-infected rats. The number of pins and play solicitations in BDV-NL pairs significantly increased over the two days of testing, while play activity in NL-BDV pairs declined on the second test day. This pattern suggests that the degree of social reinforcement on the first day of testing affected the level of play on the second day. These data demonstrate deficits in play behavior and other social interactions following BDV-associated developmental brain injury, thus supporting the value of the neonatally BDV-infected rat as an animal model of autism.

Animals↗
PubMed1996

Relationship between memory and fear: developmental and pharmacological studies.

Habituation of the acoustic startle response (ASR) and freezing responses were assessed simultaneously in rats of different ages. Results showed that until 30 days of age rats were not able to express long-term habituation of the ASR, whereas irrespective of age, all rats exhibited the increased freezing responses as a result of fear conditioning. In addition, the interaction between fear and memory was studied using the same behavioral model in adult rats treated intraperitoneally with diazepam at doses 1.2 and 2.5 mg/kg. Diazepam administration did not result in a significant change in initial startle responsiveness but elicited a profound suppression of startle amplitude over trials. Furthermore, animals given diazepam showed more initial freezing than the vehicle-treated controls, while fear-conditioned freezing was decreased by diazepam. The pattern of results is discussed in relation to developmental and pharmacological dissociations between the different behavioral components of responses to aversive and stressful cues.

Acoustic Stimulation↗
PubMedDate not supplied

Physiologic characterization of novel aggressotropic neuropeptides.

Experimental data of physiological activity of synthetic analogs of three novel neuropeptides isolated from the bovine brain are presented. The characteristics of the influence of the peptides on various forms of aggressivity of rats--intermale, predatory, and defense--with central and peripheral administration, are demonstrated. The influence of the peptides on other types of behavior--the consumption of food and water, fear, locomotor activity--associated with the formation of aggression is demonstrated. The modulatory effects of the peptides on the responses of identified neurons of molluscs to neuromediators, serotonin, dopamine, and glutamate, which participate in the neurochemical support of aggressive behavior of rats, are documented.

Aggression↗
PubMedDate not supplied

The selective effects of a monoclonal antibody against neural growth-related protein A3G7 on central mechanisms of several types of defensive behavior in adult rats.

Studies were carried out into the effects of monoclonal antibodies to protein A3G7, which is associated with the differentiation of cerebellar and hippocampal neurons, on the development, retention, and reproduction of a habituated acoustic startle response and freezing behavior in rats. Application of monoclonal antibody (50 ng) to the vermis of the cerebellum selectively disrupted the retention of long-term habituation of the acoustic startle response, while a higher dose (5 micrograms) inhibited both retention of long-term habituation of the acoustic startle response and conditioned freezing behavior. Monoclonal antibody (10 micrograms) disrupted the development and retention of short-term and long-term extinction of the acoustic startle response, as well as conditioned freezing behavior. These data provide experimental support for the systemogenesis hypothesis of behavioral acts and for the concept that there is a single molecular basis for development and learning.

Acoustic Stimulation↗
PubMedDate not supplied

[The physiological characteristics of new agressotropic neuropeptides].

Physiological effects of the structural analogs of earlier unknown neuropeptides isolated from the bovine brain were studied. It was shown that intraventricularly and intraperitoneally administered peptides strongly affected different kinds of aggressive behaviour of rats. In addition, the peptides under study influenced various kinds of behaviour presumably linked to formation of the aggressive state of the animal (food and water intake, fear, locomotion). The findings suggest that the peptides modulate dopamine-, serotonin- and glutamatergic neurotransmission which underlie neurochemical mechanisms of aggressive activity.

Action Potentials↗
PubMedDate not supplied

[The selective effect of monoclonal antibodies to the nerve growth protein A3G7 on the central mechanisms of different types of defensive behavior in adult rats].

The behavioral effects were studied of monoclonal antibodies (MA) against A3G7 protein, which is known to be associated with the processes of nervous cell differentiation. Elaboration, storage, and retention of acoustic startle (ASR) habituation and freezing behavior were tested in adult rats. The MA applied in a dose of 50 ng on cerebellar vermis selectively impaired only the ASR long-term habituation storage whereas its dose of 5 mcg impaired both long-term habituation storage and fear-conditioned freezing. Application of 10 mcg of MA disrupted the elaboration and storage of the ASR short- and long-term habituation as well as fear-conditioned freezing. The results are considered as experimental verification of systemogenesis theory and hypothesis about a common molecular basis of learning and development.

Acoustic Stimulation↗