The role of noradrenaline, dopamine and 5-hydroxytryptamine in the hyperactivity response resulting from the administration of tranylcypramine to rats pretreated with lithium or rubidium

The effect of acute lithium and rubidium pretreatment on apomorphine-induced pecking in pigeons

The effects of different doses of lithium (5-320 mg/kg intramuscularly) and rubidium (0.25 32 mg/kg intramuscularly) on apomorphine-induced pecking were investigated in pigeons. These two cations did not induce pecking by itself. Intramuscular administration of apomorphine (a mixed D1/D2 dopamine receptors agonist, 0.1-1.6 mg/kg) induced pecking in a dose-dependent manner. SCH 23390 (D1 dopamine receptor antagonist, 0.02-0.08 mg/kg) and sulpiride (D2 dopamine receptor antagonist, 25-100 mg/kg) decreased apomorphine-induced pecking dose-dependently. Combination of SCH 23390 (0.04 mg/kg) with sulpiride (50 mg/kg) caused a stronger inhibitory effect on apomorphine response. This indicates that both D1 and D2 dopamine receptors are involved in apomorphine-induced pecking. The response induced by apomorphine (0.2-0.8 mg/kg) was decreased in animals pretreated with lithium and rubidium. In these conditions, SCH 23390 and sulpiride produced a larger inhibitory effect on the apomorphine response, suggesting that acute lithium and rubidium pretreatment inhibit pecking by interfering with dopaminergic mechanisms.

The effects of rubidium, caesium and quinine on 5-HT-mediated behaviour in rat and mouse--1. Rubidium

The administration of TCP (15 mg/kg, i.p.) to rats pretreated with either intraperitoneal RbCl (3 mmol/kg, twice daily for 5 days) or dietary RbCl (30 mmol/kg diet, for 14 days), resulted in the complete 5-HT behavioural syndrome. Pretreatment with p-chlorophenylalanine (i.p. 300 mg/kg x2) or (-)-propranolol (20 mg/kg, i.p.), pindolol (4 mg/kg, i.p.) and ritanserin (0.4 mg/kg, s.c.) prevented the occurrence of the 5-HT syndrome, produced by dietary RbCl plus TCP. Intraperitoneal administration of RbCl had no effect upon the 5-HT behavioural syndrome, produced by 8-OH-DPAT (0.5 mg/kg, s.c.) or 5-MeODMT (2 mg/kg, i.p.) but enhanced the 5-HT syndrome produced by quipazine (20 mg/kg, i.p.), DOI (8 mg/kg, s.c.), p-chloramphetamine (4 mg/kg, i.p.) or by TCP plus L-tryptophan (50 mg/kg, i.p.) in rats. Dietary administration of RbCl resulted in the enhancement of the 5-HT2-mediated head-twitches in the mouse and the attenuation of hypothermia in the mouse, induced by 8-OH-DPAT (0.5 mg/kg, s.c.). The accumulation of 5-HT (after inhibition of monoamine oxidase) and the rate of synthesis of 5-HT in the whole brain (minus cerebellum) were enhanced by dietary and intraperitoneal administration of RbCl, respectively. The effects of lithium and rubidium, respectively, on 5HT function in brain are compared.

Role of brain amines in the fetal hyperpyrexia caused by tranylcypromine in LiCl-pretreated rats

Tranylcypromine (TCP), a monoamine oxidase inhibitor, caused a fatal hyperpyrexia in rats pretreated with LiCl once a day for 4 days. Pretreatment with LiCl alone did not alter the level of serotonin (5-HT), dopamine (DA) and norepinephrine (NE) in the brain. In fatal hyperpyrexia caused by LiCl plus TCP, the brain 5-HT and DA levels were increased, whereas the brain NE level was decreased. Reserpine and alpha-methyl-p-tyrosine completely prevented the hyperpyrexia, but FLA-63 did not show any effect. The hyperpyrexia was completely prevented by p-chlorophenylalanine (PCPA) given 72 hours before TCP but not by PCPA given 24 hours before TCP. Haloperidol and chlorpromazine, DA receptor blockers, inhibited the fatal hyperpyrexia, while cyproheptadine and methysergide, 5-HT receptor blockers, did not. These results suggest that DA plays an essential role in the hyperpyrexia induced by the combination of TCP and LiCl in rats, but the involvement of 5-HT is inconclusive.

[Influence of lithium and rubidium on exploratory behaviour and locomotor activity in isolated male mice (author's transl)]

The effect of lithium and rubidium on curiosity rearing, and locomotor activity in isolated and group-housed male mice (DBA/2 Han) was investigated. LiCl and RbCl were given with the drinking water (30 mol/l) during 3 weeks. The behaviour of the animals was tested before and after the chronical application of either lithium or rubidium. The results show that lithium was able to enhance the decreased curiosity of the isolated mice which now was no longer different from that of normal group-housed animals. The locomotor activity of the isolated animals was also increased by LiCl, while rearing was not altered. Rubidium even more decreased the already diminished curiosity of the 'fighting mice' but had no influence on rearing and locomotor activity. Three weeks after cessation of treatment the behaviour of the isolated mice returned to predrug levels. Neither lithium nor rubidium had any influence of the behaviour of animals kept in groups.

A novel activity cage for rats: characterization of some phenylethylamine derivatives with central stimulant and depressant effects

1. A novel activity cage for rats is described. Eight light beams are aimed at a light-conducting perspex rod at the centre of a cylindrical cage. The photoresistor at the end of the rod detects the changes in light intensity produced by interruption of the light beams. 2. The apparatus is simple to operate and was capable of detecting small differences in the motor activity of groups of rats. 3. Dose-dependent increases in motor activity were produced by dexamphetamine (1.36 to 27.3 mumol/kg, i.p.). The depressant effects produced by 20 mumol/kg doses of nonfenfluramine were greater than those of fenfluramine. Large doses (100 mumol/kg) of tranylcypromine stimulated motor activity whereas its cis-isomer, cis-2-phenylcyclopropylamine, depressed motor activity.

Effects of alpha methyltyrosine and parachlorophenylalanine on open field behavior in rats given tranylcypromine stereoisomers and lithium carbonate

Parachlorophenylalanine (PCPA) and alpha methyltyrosine (AMT) were used to study the roles of serotonin and catecholamines in hyperactivity produced by the stereoisomers of Tranylcypromine (d-Tc and 1-Tc) in male Wistar rats fed a normal diet (control groups) or a diet containing lithium carbonate (lithium groups). Components of locomotor activity were measured in an open field. Lithium decreased ambulation. d-Tc increased ambulation and caused jerky side-to-side movements. PCPA and AMT prevented the effects of d-Tc on ambulation while only PCPA prevented the effects of d-Tc on movement. 1-Tc increased ambulation. The effects of 1-Tc on ambulation were potentiated by PCPA and prevented by AMT. Rearing was increased by 1-Tc and d-Tc in rats given lithium. PCPA and AMT prevented the effects of 1-Tc and d-Tc on rearing in lithium groups. The findings suggest that the roles of serotoninergic and catecholaminergic mechanisms differ for components of open field behavior in control rats and rats given lithium.

Effects of tranylcypromine stereoisomers, clorgyline and deprenyl on open field activity during long term lithium administration in rats

Locomotor activity of male rats was studied in an open field after an i.p. injection (15 mg/kg) of the d- or l-isomers of tranylcypromine (d-Tc and l-Tc, respectively) or after s.c. injection of either clorgyline (0.5, 1 or 5 mg/kg) which selectively inhibits Type A MAO or deprenyl (0.5, 5 or 10 mg/kg) which selectively inhibits Type B MAO. The rats were fed a diet containing either no lithium (control group) or lithium chloride (lithium group) for at least 28 days prior to tests. In the control group, d-Tc increased ambulation while l-Tc, deprenyl and clorgyline failed to affect activity. In the lithium group, d-Tc and deprenyl increased ambulation, l-Tc increased ambulation and rearing, while clorgyline failed to affect activity. Lithium appeared to potentiate the behavioral effects of deprenyl and l-Tc. Symptoms of serotonin-dependent hyperactivity appeared in the control group and lithium group given d-Tc. The role of biogenic amines in the effects of the drugs on open field activity is discussed.