Effects of lithium chloride on the activity of rats tested alone or in pairs

Maintenance of conditioned place avoidance induced by gastric malaise requires NMDA activity within the ventral hippocampus

It has been reported that during chemotherapy treatment, some patients can experience nausea before pharmacological administration, suggesting that contextual stimuli are associated with the nauseating effects. There are attempts to reproduce with animal models the conditions under which this phenomenon is observed to provide a useful paradigm for studying contextual aversion learning and the brain structures involved. This manuscript assessed the hippocampus involvement in acquiring and maintaining long-term conditioned place avoidance (CPA) induced by a gastric malaise-inducing agent, LiCl. Our results demonstrate that a reliable induction of CPA is possible after one acquisition trial. However, CPA establishment requires a 20-min confinement in the compartment associated with LiCl administration. Interestingly, both hippocampal regions seem to be necessary for CPA establishment; nonetheless, inactivation of the ventral hippocampus results in a reversion of avoidance and turns it into preference. Moreover, we demonstrate that activation of dorsal/ventral hippocampal NMDA receptors after CS–US association is required for long-term CPA memory maintenance.

Neurobehavioral effects of lithium in the rat: Investigation of the effect/concentration relationships and the contribution of the poisoning pattern

Severity of lithium poisoning depends on the ingested dose, previous treatment duration and renal function. No animal study has investigated neurobehavioral differences in relation to the lithium poisoning pattern observed in humans, while differences in lithium pharmacokinetics have been reported in lithium-pretreated rats mimicking chronic poisonings with enhanced brain accumulation in rats with renal failure. Our objectives were: 1)-to investigate lithium-related effects in overdose on locomotor activity, anxiety-like behavior, spatial recognition memory and anhedonia in the rat; 2)-to model the relationships between lithium-induced effects on locomotion and plasma, erythrocyte, cerebrospinal fluid and brain concentrations previously obtained according to the poisoning pattern. Open-field, elevated plus-maze, Y-maze and sucrose consumption tests were used. In acutely lithium-poisoned rats, we observed horizontal (p<0.001) and vertical hypolocomotion (p<0.0001), increased anxiety-like behavior (p<0.05) and impaired memory (p<0.01) but no altered hedonic status. Horizontal (p<0.01) and vertical (p<0.001) hypolocomotion peaked more markedly 24h after lithium injection and was more prolonged in acute-on-chronically vs. acutely lithium-poisoned rats. Hypolocomotion in chronically lithium-poisoned rats with impaired renal function did not differ from acutely poisoned rats 24h after the last injection. Interestingly, hypolocomotion/concentration relationships best fitted a sigmoidal E_max model in acute poisoning and a linear regression model linked to brain lithium in acute-on-chronic poisoning. In conclusion, lithium overdose alters rat behavior and consistently induces hypolocomotion which is more marked and prolonged in repeatedly lithium-treated rats. Our data suggest that differences between poisoning patterns regarding lithium-induced hypolocomotion are better explained by the duration of lithium exposure than by its brain accumulation.

Acute lithium administration selectively lowers tyrosine levels in serum and brain

Lithium exerts anti-dopaminergic behavioral effects. We examined whether some of these might be mediated by changes in brain levels of tyrosine (TYR), the precursor to dopamine. Lithium chloride (LiCl(2)) 3.0mEq/kg IP acutely lowered serum TYR and the ratio of serum TYR to other large neutral amino acids (LNAAs); it also selectively lowered striatum TYR levels as measured in tissue or in vivo. While LiCl(2) 3.0mEq/kg IP also augmented haloperidol (0.19mg/kg SC)-induced catalepsy, this lithium effect was not attenuated by administration of TYR 100mg/kg IP. We conclude that lithium acutely and selectively lowers brain TYR by lowering serum levels of tyrosine relative to the LNAAs that compete with it for transport across the blood-brain barrier. However, the lowering of TYR does not appear to significantly contribute to the ability of lithium to potentiate haloperidol-mediated catalepsy.

Room novelty, sex, scopolamine and their interactions as determinants of general activity and rearing, and light–dark preferences in rats

Male and female rats were assessed for effects of scopolamine on general activity, rearing and light-dark preferences when tested in either a familiar or a novel room. Males but not females reared more often when tested in the familiar rather than novel room, and the response was increased by scopolamine for all rats combined. Whereas scopolamine increased general activity for females (but not males) in the familiar room, it decreased the response for males (but not females) in the novel room. Females crossed more often between the dark and light sides of a light-dark box and, when treated with saline but not drug, spent more time in the light side than males. Scopolamine reduced the amount of time spent in the light side for females only. While the results were discussed mainly in terms of sex differences in fearfulness, their principal value was in demonstrating the effectiveness of room novelty and sex in determining levels of the behaviors recorded, and drug responsiveness.

Lithium induces dose-related increases and decreases in activity levels in the rat

The effect of intraperitoneal lithium chloride on the activity levels of rats was measured by counting photocell interruptions in an open field. Treatment with 0.15 mEq/kg increased activity and 1.5 mEq/kg decreased activity. In a second experiment behavioral observations were added to the photocell counts of open field activity, and the increase observed with 0.15 mEq/kg LiCl in Experiment 1 was compared with the increase in open field activity produced by 0.4 g/kg ethanol. The two drugs produced similar increases in cell counts and walking, and similar decreases in sitting and sniffing. Lithium produced significantly more rearing and behavior directed at the cage than did ethanol. Following Johnson's hypothesis of lithium action, these findings are discussed within the context of lithium-induced changes in responsiveness to the environment. We suggest that, at 0.15 mEq/kg, lithium chloride might increase reactivity to the environment.

[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.

Effects of lithium on open field behavior in "stressed" and "unstressed" rats

Rats were tested for 3 min per day, for 4 successive days, in an open field apparatus, 20 min after injection of either lithium chloride (2 mEq/kg) or physiological saline. In the first experiment, the open field was illuminated with moderate white light for some rats (stress condition) and dim red light for others (non-stress condition). In the second experiment, some rats received an electric foot shock 5 h before each open field test (stress condition) and others received no foot shock (non-stress condition). In both experiments, lithium significantly reduced rearing behavior in the stressed, but not the unstressed, rats. Lithium also reduced horizontal locomotion, but this effect appeared in both stressed and unstressed rats. In the second experiment, defecation was measured, and it was found that lithium-treated rats defecated less than saline-treated rats in the first session, but not in subsequent sessions, due to habituation which occurred for the saline rats.

Lithium effects upon components of activity in rats

When lithium chloride was administered to rats several changes occurred in a number of components of activity, some of which were sex-related. There was a reduction in both ambulatory and rearing activity and in behaviour associated particularly with the mouth and nose. The findings are related to a suggestion that lithium effects on behaviour may be more subtle than hitherto thought.

Voluntary lithium intake, antidotal thirst' and concurrent behavior of rats

1 Voluntary intake of various pair combinations of fluids (100 mM, 10 mM LiC1, 10 mM NaC1, water) and body weight was measured daily in rats. 2 More lithium was consumed when water was available. 3 When offered a lithium-sodium choice the rats did not consume significantly more saline than water on the previous trial. While saline consumption increased over the two days, lithium decreased slightly. 4 Following the lithium-only trial, water and saline were provided. Marked polydipsia was observed on the first day and the rats drank more water than saline. On the second day there was a significant drop in saline intake while water consumption returned to baseline levels. 5 Behavioural measurements overall confirmed the depressant effect of lithium: decreased ambulation and rearing and increased time spent immobile/grooming. 6 These findings are discussed with reference to lithium toxicity, which may be a comfounding variable in studies concerned with the effects of this salt on the behavior of laboratory rodents. Behavioural irritability such as aggression reported in situations using long-term lithium treatment may be reduced by provision for voluntary saline consumption.

Modifications by lithium of behavioral responses to methamphetamine and tetrabenazine

Different groups of mice were injected s.c. daily with lithium chloride in three doses(0.52, 1.58 and 4.72meg/kg) or with saline for a period of 3 weeks. Lithium administered acutely or chronically did not affect spontaneous locomotor activities. However, methamphetamine-induced hyper-locomotor activities were inhibited in the lithium groups as compared with those in the saline group, while the hyper-locomotor activities induced by tetrabenazine in the nialamide-pretreated animals were reduced to some extent but not significantly by lithium. Tetrabenazine brought about an initial transient increase followed by a decrease of spontaneous locomotor activities in the lithium groups, whereas it induced only a decrease of the activities in the saline group. In addition, jumping and vertical jumping behaviors, which were not observed in the saline group, occurred 30-60 min after tetrabenazine in the lithium groups. These effects of lithium tended to increase with an increase of the doses administered and with a prolongation of its daily administration. The results demonstrate that lithium modifies behavioral responses to methamphetamine and tetrabenazine.