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R Brus

Publications and source records attributed to R Brus.

At least 19 recordsLinked to original sources
PubMed1979

Mediation of central prostaglandin effects by serotoninergic neurons.

Ten days after administration of 5,6-dihydroxytryptamine, which causes degeneration of central serotoninergic neurons, the depressive behavioral effects of PGF2 alpha and PGE2 were evidently inhibited. Central chemical serotoninectomy abolished the hyperthermic and hypertensive effects of PGF2 alpha, but only slightly affected those of PGE2. It is concluded that serotoninergic neurons mediate the depressive behavioral action of both PGF2 alpha and PGE2. They also mediate the hyperthermic and hypertensive action of PGF2 alpha but not of PGE2. This suggests that these prostaglandins have different central modes of action.

5,6-Dihydroxytryptamine↗
PubMed1979

Effect of prostaglandin F2 alpha on temperature and behaviour of centrally sympathectomized rats.

Prostaglandin F2 alpha (PG F2 alpha) in doses of 1 and 10 micrograms applied intraventricularly causes a rise in body temperature and exerts a sedative action on rat behaviour. Chemical sympathectomy of the central nervous system (CNS) induced by a twofold intraventricular administration of 250 micrograms of 6-hydroxydopamine reduces the influence of PG F2 alpha on the body temperature and behaviour. Reserpine administered to rats with chemical sympathectomy of the central nervous system reverses or prevents the PG F2 alpha action on body temperature of the animals. The results of the experiments seem to indicate that the central monoaminergic mechanisms play a role in the central action of PG F2 alpha on body temperature and behaviour.

Animals↗
PubMed1978

Influence of polyphloretin phosphate on the central effects of prostaglandin E2 and F2alpha in rats.

The possibility that polyphloretin phosphate (PPP) antagonizes the central effects elicited by prostaglandin (PG) E2 and F2alpha was investigated. PPP was administered i.c.v. to male Wistar rats (10 or 25 microgram) 10 or 30 min before i.c.v. injection of PGF2 or PGF2alpha (1 or 10 microgram). The duration of several component of behavior, the degree of irritability, and the rectal temperature of rats were measured; the levels of noradrenaline, dopamine, 5-hydroxytryptamine, and 5-hydroxyindoleacetic acid were measured spectrophoto-fluorometrically in discrete brain areas. PPP antagonized temperature and behaviroal changes induced in rats by PGF2alpha, but not those induced by PGE2. The magnitude of antagonism depended on the dose of PPP and on the time of the pretreatment before PGF2alpha administration. Changes in the level of biogenic amines in discrete brain areas evoked by PGs were not affected by PPP. We found that PPP antagonizes the central effects of PGF2alpha but not those of PGE2, and that changes of biogenic amines in discrete brain areas elicited by PGs are not specific.

Animals↗
PubMed1977

Behavior of rats in various stages of the sexual cycle after injection of noradrenaline into the lateral ventricle of the brain.

The influence of intraventricular injection of 50 microng of noradrenaline (NA) on behavior of female Wistar rats in various phases of the sexual cycle, and the influence of 17-beta-estradiol and progesterone in castrated female rats were studied. Changes in motor and exploratory activity were observed in the course of the sexual cycle in female rats. Sensitivity to NA injected intraventricular varied significantly in different phases of the sexual cycle. Castration depressed the action of NA on motor and exploratory activities in rats, and progesterone prevented the depressive effect of NA in castrated rats.

Animals↗
PubMed1976

Influence of 6-hydroxydopamine on the behavioral effects induced by apomorphine or clonidine in rats.

The aim of this paper is to examine if central chemical sympathectomy induced by two injections of 6-hydroxydopamine (6-OHDA) in a dose of 250 mug intracerebroventricularly (i.c.v.) affects behavioral phenomena elicited by apomorphine (AP) (1 or 1.2 mg/kg i.p.) or clonidine (CL) (0.1 MG/KG, 5 Or 1 mug/kg i.p.). Experiments were carried out on male Wistar rats. The time of duration of several components of behavior and the degree of irritability of rats were measured. Moreover, open field and hole test were performed. The lower dose of AP did not affected behavior of rats. The higher dose increased the locomotor and exploratory activity of animals. 6-OHDA potentiated these effects of AP. CL (0.1 mg/kg) had a depressive effect on the rats' behavior, which was potentiated by 6-OHDA. CL (5 mug/kg) had no effect on the rats' behavior, but in a dose of 1 mug/kg caused excitatory behavior. This type of behavior was abolished by 6-OHDA. In conclusion, central chemical sympathectomy caused increased sensitivity of the central nervous system on AP. Excitatory behavioral effects of CL in low dosage may be connected with stimulation of central adrenergic receptors. Depressive behavioral effect of CL in high dosage is unspecific. Central chemical sympathectomy affects by different methods the reactivity of dopaminergic and noradrenergic neurons.

Animals↗
PubMed1976

The effect of central chemical sympathectomy on the oxygen uptake; anaerobic glycolysis and lactic acid dehydrogenase activity in the retina of white rats.

Male Wistar rats were injected intraventricularly with two doses of 250 mcg of 6-hydroxydopamine (6-OHDA) in two consecutive days. Two weeks later the oxygen uptake, anaerobic glycolysis and lactic acid dehydrogenase (LDH) activity in the retina were determined. The decrease of oxygen uptake (-28%), anaerobic glycolysis (-31%) and LDH activity (-12%) in rats treated with 6-OHDA in comparison to control animals was found. The possible role of the adrenergic system in regulation of the metabolism of the retina is discussed.

Anaerobiosis↗
PubMed1976

Central action of prostaglandin F2alpha on circulatory system in rats.

PGF2alpha administered into the lateral brain ventricle of anesthetized rats caused an increase of the blood pressure and heart rate. Reserpine, chemical sympathectomy of the CNS with 6-hydroxydopamine (6-OHDA), atropine, and vagotomy weakened the central action of PGF2alpha on the peripheral circulation. Propranolol and phenoxybenzamine exerted no influence. Neither reserpine nor 6-OHDA changed the influence of iv injected PGF2alpha on the circulation. The results of the experiments indicate to the participation of the central catecholamines in the mechanism of central action of the PGF2alpha on the circulatory system.

Animals↗
PubMed1976

Behavioural effects of dopamine and 5-hydroxytryptamine in centrally chemosympathectomized rats.

In rats central chemical sympathectomy (CCS) was elicited by intracerebro-ventricular (icv) injection of two doses of 250 mug of 6-hydroxydopamine (6-OHDA) at 48 hr interval. 7 days after the last injection when full CCS is developed, 10 mug of dopamine (DA) or 5-hydroxytryptamine (5-HT) were applied icv and locomotor and exploratory activity and irritability of animals were measured. CCS reversed the depressive effect of DA on the locomotor and exploratory activity, and intensified irribability of animals. It intensified the effect of 5-HT on the exploratory activity without changing the others observed behavioral parameters. It is concluded that CCS changes reactivity of central nervous system of pharmacological effects of DA and slightly affects the central response to 5-HT.

Animals↗
PubMed1976

The influence of central chemical sympathectomy and reserpine on peripheral effects of noradrenaline and cyclic AMP dibutyrate injected into the cerebral ventricles.

Chemical sympathectomy of the central nervous system by injection of 6-hydroxy-dopamine (2 X 250 mug) or 6-hydroxydopa (90 mug) intensified some of the peripheral effects of noradrenaline and cyclic AMP dibutyrate injected into the cerebral ventricles. Reserpine (5 mg/kg) injected intraperitoneally weakened the peripheral reactions to noradrenaline injected intraventricularly. The results of the experiments indicate that peripheral reactions to intraventricularly injected noradrenaline depend on changes in the content of endogenous narodrenaline in the brain and on the mechanisms leading to these changes.

Animals↗
PubMed1976

The influence of ATP and AMP injected into the lateral ventricles of the brain on behavior in rats.

The influence of ATP and AMP injected into the lateral cerebral ventricle in doses of 50, 100 and 200 mug on behavior in rats was studied. ATP in the doses administered had no effect on behavior of rats. AMP in these doses enhanced motor activity of the rats. Chemical sympathectomy by intracerebral injection of 6-hydroxy-dopamine did not affect the action of either of the compounds on behavior of rats. AMP potentiated the action of intracerbrally administered noradrenaline on behavior of the animals.

Adenosine Monophosphate↗
PubMed1975

The impairment of learning of conditioned avoidance response in rats after 6-hydroxydopamine.

Intraventricular injection of 250 mug of 6-hydroxydopamine, twice in two days apart caused a complete abolition of learning of conditioned avoidance response (CAR) in rats. L-DOPA in a dose of 100 mg/kg and then in a dose of 200 mg/kg 1. p. injected during several days did not restore the learning of CAR. This indicates that intact catecholaminergic neurons are essential for the learning of CAR. We suggest that different brain mechanisms are involved in learning and maintaining gross locomotor behavior.

Animals↗