Effects of chronic citalopram treatment on central and peripheral spontaneous open-field behaviours in rats

The spontaneous open-field behavioural effects of 10 days of chronic treatment with two clinical doses (10 and 20 mg/kg daily) and one high/toxic dose (100 mg/kg daily) of the selective serotonin reuptake inhibitor citalopram (delivered subcutaneously by implanted osmotic pumps) were examined in rats. Central and peripheral arena locomotor and rearing activities were recorded simultaneously, and the data were assessed during the first hour as well as during the following 24 hr (the latter for effects on the diurnal rhythm). Rats treated with 100 mg/kg daily exhibited lower peripheral locomotor and rearing activities than the other groups during the first test hour. The ratio between central and peripheral activity increased in a dose-dependent non-proportional manner during the first test hour, indicating a general increase in the central arena activity exerted by the rats when treated with citalopram. No major differences were observed between any of the four groups in overall behavioural activities over the 24-hr period. This study indicated that the open-field locomotor and rearing behaviours in normal rats were affected by increasing doses of racemic citalopram, particularly during the first hour of adaptation

Open-field behavioural alterations in liver-impaired and sham-operated rats after acute exposure to the antidepressant venlafaxine

Patients with chronic liver impairment often display symptoms of affective psychiatric nature where the choice for antidepressant treatment is rational. Since caution is recommended when these drugs are used in such patients, a dose reduction is usually performed. We have previously reported that a dose reduction to liver-impaired portacaval shunted rats has resulted in similar brain concentrations of venlafaxine as compared to sham-operated control rats that received a two times higher dose. The main aim of the present study was therefore to investigate if this "normalisation" in pharmacokinetics of the portacaval-shunted rats also was true for the pharmacodynamic response in terms of drug effect on spontaneous open-field behaviour. Thus, portacaval-shunted rats received a single reduced dose (5 mg/kg) of venlafaxine or saline, whereas sham-operated rats received either 10 mg/kg or saline. Thereafter, central and peripheral arena locomotor and rearing activities were recorded during 60 min. The venlafaxine-treated portacaval-shunted and sham rats displayed reduced and unchanged overall behavioural activities compared with corresponding controls, respectively. However, the ratios between centrally and peripherally performed behavioural activities were higher in the venlafaxine-treated sham rats, indicating an increase in central arena activity as compared to the sham-saline and portacaval-shunted rats. The present study indicates that, despite a 50% dose reduction, caution still is necessary when antidepressants are used in liver insufficient subjects. This study also shows the importance of detailed open-field behavioural studies in which both central and peripheral activities are recorded for measurement of open-field behavioural drug effects

Muscle histochemistry in chronic alcoholism

Twenty-two chronic acoholic patients were assessed by neurologic examination and muscle biopsy. The patients manifested proximal muscular weakness to a variable extent. One case presented as an acute bout of myopathy, according to the Manual Muscle Test, MMT. The most prominent histologic feature observed was muscle atrophy (95.3%) better evidenced through the ATPase stain with the predominance of type II A fibers (71.4%). Lack of the mosaic pattern (type grouping) seen in 76% of the cases and an important mitochondrial proliferation with intrasarcoplasmatic lipid accumulation in 63% of the patients. In case of acute presentation of muscle weakness the. pathological substrate is quite different, i.e. presence of myositis mainly interstitial characterized by lymphoplasmocytic infiltrate and several spots of necrosis like Zencker degeneration. Based on histologic criteria, our data suggest that: the main determinant of muscle weakness seen in chronic alcoholic patients is neurogenic in origin (alcoholic polineuropathy); the direct toxic action of ethanol under the skeletal muscle is closely related to the mitochondrial metabolism; the so-called acute alcoholic myopathy has probably viral etiology