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Biomedical subjects

B J Meyerson

Publications and source records attributed to B J Meyerson.

At least 19 recordsLinked to original sources
PubMed1991

The novel 5-HT1A receptor antagonist (S)-UH-301 antagonizes 8-OH-DPAT-induced effects on male as well as female rat copulatory behaviour.

The 5-HT1A receptor agonist 8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT) facilitates male rat copulatory behaviour but inhibits female rat copulatory behaviour. The effect of the novel 5-HT1A receptor antagonist (S)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin [S)-UH-301) on these 8-OH-DPAT-induced responses was tested. 8-OH-DPAT was given s.c. in a dose of 0.176 mumol/kg (50 micrograms/kg). The doses of (S)-UH-301 given s.c. were 1.76 mumol/kg (0.53 mg/kg) and 5.28 mumol/kg (1.60 mg/kg). The administration of (S)-UH-301 10 min before 8-OH-DPAT antagonized the 8-OH-DPAT-induced effects on both male and female rat copulatory behaviour. The results presented strongly support the classification of (S)-UH-301 as a 5-HT1A receptor antagonist. In addition, the effect of the enantiomer of (S)-UH-301, (R)-5-fluoro-8-hydroxy-2-(dipropylamino)tetralin [R)-UH-301), on male rat copulatory behaviour was tested. This enantiomer was found to facilitate male rat copulatory behaviour in a 8-OH-DPAT-like manner, supporting a 5-HT1A agonistic action of (R)-UH-301.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1991

Neonatal exposure to substance P alters behavioral and substance P levels in the central nervous system of the adult rat.

Substance P (SP) administered subcutaneously to male and female rats during a neonatal period (days 1-7 after birth), produced long-term effects. Thermal/pain perception and elements of both male and female copulatory behavior were altered. A significant increase in the SP level in the dorsal part of the spinal cord was demonstrated by radioimmunoassay and by micro-fluorescence. The present study indicates that exposure to SP during the neonatal period, when the role of SP in transmission is likely to be established, has biochemical and functional consequences for SP systems in the adult.

Animals↗
PubMed1991

The effects of long-term treatment with 8-OH-DPAT on the lordosis response and hypothermia in female rats.

The effects of long-term treatment with a low dose of the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) on steroid hormone-dependent copulatory behaviour in female rats, the lordosis response, and on the hypothermic response of female rats were studied. Female rats were treated for 15 days, once daily, and tested on days 1 and 15 of treatment. They received 25 micrograms/kg on test days and 50 micrograms/kg on all other days. Subsensitivity was not induced to the inhibitory effect of 8-OH-DPAT on the lordosis response. In contrast, however, the acute effect of 8-OH-DPAT on body temperature was abolished by the long-term treatment. The results presented indicate that the induction of subsensitivity to the effects of 8-OH-DPAT is not primarily dependent on the pre- or post synaptic locus of action. Our data suggest that hormonal mechanisms are involved.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1990

The long-term effects of 8-hydroxy-2-(di-n-propyl-amino)tetralin (8-OH-DPAT) on copulatory and exploratory behaviour in male rats.

The long-term effects of low doses of the 5-HT1A-agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), were studied to assess differences in the development of subsensitivity in 8-OH-DPAT-induced behavioural responses. Male rats received 33 or 100 micrograms/kg per day s.c. for 8 or 15 days. The chronic treatment did not alter the facilitatory effects of 8-OH-DPAT on male copulatory behaviour. In contrast, the effects on exploratory activity and the induction of flat body posture observed after the acute treatment were attenuated by prolonged administration of 8-OH-DPAT. The results presented indicate that gonadal hormones are involved in 5-HT receptor regulatory mechanisms.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1989

Aging and sociosexual behavior in the male rat.

Senescent and young rats have been studied in a copulatory test and sociosexual approach test. The copulatory test was applied to investigate age-dependent changes in the copulatory capacity in the rat. The sociosexual approach test was used to describe motivational aspects of this behavior. Latencies, frequencies and durations of copulatory behaviors in the copulatory test and visits to various incentive animals in the approach test have been measured. Senescent rats had longer latencies and less frequencies of copulatory behaviors. In the approach test they showed less visits to the estrous female. Data were also subjected to a correlational analysis in order to relate the findings of the two tests. It is concluded that aged male rats differ from young ones in organizing their behavior in relation to time, are less social and have a less pronounced social preference pattern. In addition, the coherence between various elements of copulatory behavior was less in the senescent rat than in the young male rat, whereas the social approach patterns are more coherent in the aged male.

Aging↗
PubMed1985

Increased investigative activity after presynaptic dopaminergic stimulation measured by a fixed-interval recording procedure.

A fixed-interval recording procedure was used to study the effects of catecholaminergic agonists and antagonists on the exploratory behaviour pattern in male rats. One particular element of this pattern, the investigative behaviour, was found to be sensitive to drugs acting on both noradrenaline and dopamine receptors. An increase in investigative activity (IA) and a slight decrease in the other exploratory (OE) activity was caused by alpha-methyl-p-tyrosine. The alpha 2-receptor agonists clonidine and B-HT 933 decreased both the IA and the OE activity. These effects were counteracted by yohimbine. Activation of presynaptic dopamine receptors by low doses of apomorphine (less than or equal to 0.2 mg/kg) and B-HT 920 resulted in significant increase in IA and a decrease in OE activity. Higher doses of apomorphine (0.7 and 1.0 mg/kg) decreased or abolished IA but increased OE activity. We assume this effect to be due to postsynaptic receptor stimulation. Pretreatment with haloperidol counteracted the effects of apomorphine and B-HT 920. An increase in IA is probably due to a decrease in dopaminergic activity, which can be induced by presynaptic receptor activation. The decrease in IA after presynaptic noradrenergic stimulation cannot at present, however, be related to a specific influence, since the possibility of general effects on locomotion cannot be ruled out. The increase in IA observed after presynaptic dopaminergic activation and the fixed-interval recording procedure may be valuable instruments in the search for selectively acting compounds with dopaminergic activity.

Adrenergic alpha-Agonists↗
PubMed1985

Influence of early beta-endorphin treatment on the behavior and reaction to beta-endorphin in the adult male rat.

A study was made of the influence of early exposure to beta-endorphin (beta-END) on the adult behavior and response to beta-END in male rats. beta-END was given during a neonatal period, at 1-5 days of age (1 microgram/animal/day s.c.). Recordings of the development of home-nest-orientation ability, body weights, and sex-specific approach behavior showed that the early beta-END treatment did not have debilitating or other non-specific effects. The early beta-END treatment did cause significant changes in the establishment of the adult pattern of sex-specific approach behavior. Copulatory behavior was not apparently influenced. Intracerebroventricular injection of beta-END (1 microgram) at an adult age induced changes in exploratory and copulatory behaviors and in the pattern of sex-specific approach behavior. The reaction to this treatment with respect to components of socio-sexual behavior differed significantly between males treated early with beta-END and their corresponding controls. No differences were observed in behaviors in the exploratory test situation. It is concluded that early beta-END treatment in rats influences components of socio-sexual behavior and the response to exogenous beta-END in adulthood.

Animals↗
PubMed1985

Effects of ACTH1-24 on male rat behavior in an exploratory, copulatory and socio-sexual approach test.

The effect of intraventricular application of ACTH1-24 on exploratory behavior, excessive grooming, and socio-sexual behavior in male rats was studied. It appeared that ACTH1-24 (1 microgram/animal) affects both excessive grooming and exploration. Sexual performance was delayed, as expressed in latency time to ejaculation, probably because of prolonged grooming behavior. The behavioral effects of ACTH are explained in terms of enhanced attention to external stimuli.

Adrenocorticotropic Hormone↗
PubMed1979

Hypothalamic hormones and behaviour.

In recent years evidence has accumulated that hypothalamic hormones may influence behaviour directly, independently of their hypophysiotropic effects. Such a dual role has also been shown for several peptide hormones of pituitary and peripheral origin. The present synopsis is concerned with the effects of neuropeptides on spontaneous behaviour, acquired responses in certain psychological test situations, and drug-induced behavioural effects. A growing body of evidence suggests, that neuropeptides are involved in different behavioural processes. Some peptides selectively influence behaviours such as feeding, drinking, sexual responses etc. Other neuropeptides seem to influence behaviour by acting on processes which are a common integral part of the production of behaviour, namely the ability to receive environmental stimuli, to consolidate, retain and retrieve information. The insight into these mechanisms is important for the understanding of mental disturbances and in order to find specific therapy.

Animals↗
PubMed1978

Long term effects of social deprivation during early adulthood in the mongolian gerbil (meriones unguiculatus).

The influence of isolation on male-female relationships was investigated. Animals isolated between 90 and 200 days of age showed more agonistic behaviour in paired encounters than controls. This difference disappeared when the animals had been housed with a cagemate. A secondary isolation late in life resulted in a more rapid onset of agonistic behaviour in the early isolates than in the controls. Thus it is concluded that the early isolation had a lasting influence, which only became evident after renewed isolation treatment.

Age Factors↗
PubMed1977

A comparative study of different amphetamines on copulatory behavior and stereotype activity in the female rat.

The influence of D- and L-amphetamine, fenfluramine, and p-chloroamphetamine on female copulatory behavior (lordosis response) and the induction of stereotype activity was compared. Lordosis response in the female rat has been shown to be inhibited by increased central nervous serotonergic (5-HT) as well as dopaminergic (DA) activity. A dose-dependent inhibitory effect on the estrogen- + progesterone-induced lordosis response in ovariectomized rats was demonstrated after treatment with the four amphetamines. In contrast, only D- and L-amphetamine induced a stereotype activity, which is considered to be mediated by DA mechanisms. A decrease in DA receptor activity, achieved by pimozide pretreatment, abolished the effect of D-amphetamine on lordosis behavior, but the effect of L-amphetamine was only slightly diminished and the action of fenfluramine and p-chloroamphetamine was unaffected. On the other hand, both L- and D-amphetamine-induced stereotype activity was prevented by pimozide treatment. The data suggest that the D-amphetamine effect on lordosis behavior is mediated by increased DA receptor activity. Although it induces stereotype activity by increased DA activity, L-amphetamine, like fenfluramine and p-chloroamphetamine, inhibits the lordosis response by some other action presumably related to serotonergic mechanisms.

Amphetamine↗
PubMed1977

The effects of different amphetamines on copulatory behaviour and stereotype activity in the female rat, after treatment with monoamine depletors and synthesis inhibitors.

The effects of treatment with alpha-methyl-p-tyrosine (alphaMPT), parachlorophenylalanine (pCPA) and reserpine in combination with D- or L-amphetamine on copulatory behaviour and stereotype activity was studied in estrogen + progesterone treated ovariectomized rats. In doses which clearly prevented D- and L-amphetamine-induced stereotype activity alphaMPT or pCPA did not influence the effect of D- and L-amphetamine on lordosis response. Reserpine treatment decreased the enhanced stereotype activity after D- and L-amphetamine but did not decrease the effect on the copulatory behaviour. Pretreatment with pCPA or reserpine clearly reduced the effect of fenfluramine on the lordosis response. It is suggested that different mechanisms of action are involved in the D-amphetamine effect on the lordosis response and on stereotype activity. The present data give further evidence that the lordosis inhibitory effect of fenfluramine is mediated by 5-HT-mechanisms. The mechanism by which L-amphetamine inhibits the lordosis response seems to be different from both the action of fenfluramine and the effect of D-amphetamine.

Amphetamines↗
PubMed1976

Comparison of the action of lysergic acid diethylamide and apomorphine on the copulatory response in the female rat.

The effects of lysergic acid diethylamide (LSD) and apomorphine were compared using female copulatory behavior (lordosis response), in ovariectomized estrogen + progesterone-treated rats. Both serotonin and dopamine are implicated in the inhibition of this behavior. Each compound inhibited lordosis behavior dose dependently and with a similar time-course. Pimozide (0.1; 0.5 mg/kg) blocked the apomorphine (0.2 mg/kg)-induced decrease of lordosis response, while only a certain abbreviation of the LSD (0.10 mg/kg) inhibition was achieved by pimozide (0.5 mg/kg). Chlorpromazine (0.5 mg/kg) in a dose without effects on lordosis of its own had an action similar to pimozide on the LSD effect. It is concluded that the predominant action of LSD on the female copulatory response is not mediated by increased dopamine receptor activity but that the LSD effect might be modulated by decreased dopaminergic activity.

Animals↗