Galantamine as a preventive of diisopropylphosphorofluoridate toxicity effects in rat brain.

Diisopropylfluorophosphate exerts its toxic effect by irreversibly inhibiting acetylcholinesterase. This results in over-stimulation of central and peripheral cholinergic activity. The aim of the present study was to evaluate the possible preventive effects of acute treatment with reversible acetylcholinesterase inhibitor galantamine against the signs of cholinergic toxic syndrome provoked by diisopropylfluorophosphate, such as hypothermia, muscular fasciculations, oral dyskinesia and decreased locomotor performance in a rat model of intoxication. The effects of these two anticholinesterases on acetylcholinesterase activity and on the expression of mRNA of the immediate early response gene c-fos in the brain were assessed by histochemical acetylcholinesterase staining and by in situ hybridization, respectively. Diisopropylfluorophosphate induced rapidly progressing hypothermia, muscular fasciculations, oral dyskinesia and decreased locomotor performance. The increased cholinergic cortical and hippocampal activity due to irreversible acetylcholinerase inhibition were indicated by the increased c-fos mRNA autoradiographic signal and by the inhibition of acetylcholinesterase staining, respectively. Galantamine by itself provoked transient and relatively weak inhibition of the acetylcholinesterase staining, while it did not induce increased c-fos mRNA expression or significant behavioural signs of cholinergic toxicity. Galantamine significantly reduced the rate of the onset, but not the maximal hypothermia induced by diisopropylfluorophosphate. Importantly, all the above-mentioned behavioural and neurochemical effects of diisopropylfluorophosphate were significantly reduced by galantamine. These results indicate that the acute pre-treatment with galantamine may have prophylactic effects against the intoxication by diisopropylfluorophosphate.

Delirium during i. v. citalopram treatment: a case report.

This paper reports the case of a 65-year-old depressed man without somatic illnesses in whom monotherapy with i. v. citalopram induced delirium. He was admitted to a closed geriatric ward as a psychotically depressed patient with somatic and depressive delusions, and suicidal thoughts. Because he rejected all oral medications, monotherapy was initiated with 20 mg of i. v. citalopram per day. After 3 days, he became delirious and physically aggressive. This description of acute hyperkinetic delirium associated with i. v. citalopram therapy is the first one of this kind addressing side effects of i. v. citalopram.

The association between catechol-O-methyl-transferase Val108/158Met polymorphism and suicide.

One of the candidate genes for suicide is also a gene in the pathway for catecholamine degradation encoding an enzyme catechol-O-methyl-transferase (COMT). It harbors a common functional polymorphism, a G to A nucleotide transition resulting in amino acid substitution from valine (Val) to methionine (Met) at position 158 (COMT Val(108/158) Met; rs4680), that has been associated with psychiatric disorders characterized with an increased risk of suicidal behavior. We have performed the first study on Caucasian population examining the association between completed suicide and the COMT Val(108/158) Met polymorphism. The study population consisted of 356 suicide victims and 198 control subjects. Significant difference in COMT Val(108/158) Met variants' (genotypes, alleles and Val carriers) distribution was found only in male groups, between controls and suicide victims (P = 0.018, P = 0.031, P = 0.005), and between controls and violent suicide victims (P = 0.026, P = 0.042, P = 0.010). The r value from the standardized residuals showed that the Met/Met genotype (r = 2.03) in the control group contributed to these significant differences. In contrast to male subjects, no significant differences in the frequency of the COMT Val(108/158) Met variants were detected between female control and female suicide groups; however, the power of calculation (range 0.161-0.680) was below the desired 0.800. In addition, the logistic regression analysis confirmed these significant differences. In conclusion, our results showed the overpresentation of the Met/Met genotype in male control subjects compared with male suicide victims, suggesting that this genotype of the COMT Val(108/158) Met might be a protective factor against suicide.

Donepezil inhibits diisopropylfluorophosphate-induced seizures and up-regulation of synaptotagmin 4 mRNA.

Reversible acetylcholinesterase inhibitor donepezil displays prophylactic effects against intoxication with irreversible organophosphorous acetylcholinesterase inhibitors. We used behavioural observation of yawning and epileptic seizures, histochemical acetylcholinesterase staining, and in situ hybridization of the immediate early genes, c-fos and synaptotagmin 4 (Syt4) mRNAs in the brain, to evaluate whether donepezil could protect the brain against the effects of the organophosphate anticholinesterase, diisopropylfluorophosphate, in a rat model of intoxication. Diisopropylfluorophosphatetreated animals exhibited frequent yawning, significant inhibition of acetylcholinesterase staining and upregulation of c-fos mRNA, but not the epileptic seizures or significant change of Syt4 mRNA levels. In order to reduce the threshold for the induction of cholinergic seizures, additional groups of rats were pre-treated with LiCl 24 h before the treatment with diisopropylfluorophosphate. These rats exhibited the seizures, a significant inhibition of acetylcholinesterase staining and significant upregulation of c-fos and Syt4 mRNA levels. All the above-mentioned effects of diisopropylfluorophosphate were inhibited by donepezil pre-treatment. Donepezil pre-treatment by itself induced only a comparatively weaker inhibition of acetylcholinesterase staining and infrequent yawning. We conclude that donepezil protects the brain against diisopropylfluorophosphate-induced effects and that Syt4 mRNA upregulation may serve as a novel marker for organophosphate-induced seizures.

Intramuscular olanzapine vs. intramuscular short-acting antipsychotics: safety, tolerability and the switch to oral antipsychotic medication in patients with schizophrenia or acute mania.

BACKGROUND: This study compared the safety, tolerability and switch to oral medication in patients with bipolar disorder or schizophrenia who received intramuscular (IM) olanzapine or other IM antipsychotics for the treatment of acute agitation. METHODS: Patients (N = 2011) from 15 countries participated in this prospective, observational, non-interventional study. Inpatients requiring treatment with at least one IM injection of a short-acting antipsychotic were assessed at baseline and within 7 days after the first IM injection. Treatment groups comprised: (i) patients prescribed IM olanzapine at baseline; and (ii) patients prescribed any other IM antipsychotic medication at baseline. Outcome measures included: treatment-emergent adverse events, concomitant psychotropic medication and the time taken to switch to oral medication. RESULTS: Fewer patients in the IM olanzapine group experienced an adverse event than patients in the other IM antipsychotic group (34.4% vs. 46.2%, p < 0.001). The most frequently reported adverse events in both groups were: sedation, Parkinsonism, disturbance in attention, akathisia, dystonia and orthostatic hypotension. Fewer patients in the IM olanzapine group used anticholinergics (13.9% vs. 42.5%, p < 0.001) or anxiolytics/hypnotics (47.6% vs. 51.6%, p = 0.023). Patients in the IM olanzapine group switched to oral medication earlier than patients in the other IM antipsychotic group (median time = 46.5 vs. 48.0 h, p = 0.009). CONCLUSIONS: These findings suggest that IM olanzapine may have a favourable impact on individual patients. However, the high rate of oral concomitant medication used throughout the study limits these findings from being associated with IM olanzapine alone.

Effect of thyroid hormones on acetylcholinesterase mRNA levels in the slow soleus and fast extensor digitorum longus muscles of the rat.

In the rat, the level of acetylcholinesterase messenger RNA in the typical slow soleus muscles is only about 20-30% of that in the fast extensor digitorum longus muscles. The expression of contractile proteins in muscles is influenced by thyroid hormones and hyperthyroidism makes the slow soleus muscle faster. The influence of thyroid hormones on the levels of acetylcholinesterase messenger RNA level in the slow soleus and fast extensor digitorum longus muscle of the rat was studied in order to examine the effect of thyroid hormones on muscle acetylcholinesterase expression. Hyperthyroidism was induced in rats by daily thyroid hormone injection or thyroid hormone releasing tablet implantation. Hind-limb suspension was applied to produce muscle unloading. Muscle denervation or reinnervation was achieved by sciatic nerve transection or crush. Acetylcholinesterase messenger RNA levels were analyzed by Northern blots and evaluated densitometrically. Hyperthyroidism increased the levels of acetylcholinesterase messenger RNA in the slow soleus muscles close to the levels in the fast extensor digitorum longus. The effect was the same in the unloaded soleus muscles. Acetylcholinesterase expression increased also in the absence of innervation (denervation), in the presence of changed nerve activation pattern (reinnervation), and under enhanced tonic neural activation of the soleus muscle (electrical stimulation). However, the changes were substantially smaller than those observed in the control soleus muscles. Enhancement of acetylcholinesterase expression in the soleus muscles by the thyroid hormones is, therefore, at last in part due to hormonal effect on the muscle itself. On the contrary, increased level of the thyroid hormones had no influence on acetylcholinesterase expression in the normal fast extensor digitorum longus muscles. However, some enhancing influence was apparent whenever the total number of nerve-induced muscle activations per day in the extensor digitorum longus muscle was increased. Thyroid hormones seem to be an independent extrinsic factor of acetylcholinesterase regulation in the slow soleus muscle.

Effect of mechanical load on acetylcholinesterase mRNA levels in the slow soleus muscle of the rat.

The influence of mechanical load on the levels of acetylcholinesterase (AChE) mRNA was studied in order to examine to which extent different loading conditions may be responsible for differences in AChE regulation between the soleus, which is an antigravity muscle, and the fast EDL muscle. Forty-eight female rats were randomly assigned to three groups: a group with hindlimb suspension producing soleus muscle unloading, a group with ablation of synergistic gastrocnemius muscle causing overload of the soleus muscle, and the control group. The soleus muscles were isolated after 8 days of treatment AChE mRNA levels were analyzed by Northern blots and evaluated densitometrically. The values were normalized with beta-actin mRNA level, and then a value of 100% was assigned to the mRNA level in the control EDL muscle. Muscle unloading did not produce a significant increase of the AChE transcript levels, but the levels were rather variable. However, a statistically significant increase of AChE mRNA levels was observed in overloaded soleus muscles. These results corroborate the hypothesis that the slow and fast patterns of activity appear more important then muscle loading for the differences in regulation of AChE mRNA levels in fast and slow muscles.