Antidepressant drugs: imipramine, mianserin and trazodone

A bimetallic PdCu–Fe3O4 catalyst with an optimal d-band centre for selective N-methylation of aromatic amines with methanol

Highly efficient and selective N-methylation of aniline with methanol is possible with Pd1Cu0.6–Fe3O4 nanoparticle catalyst.

Sleep Disorders in Stroke: An Update on Management

Stroke is a leading cause of disability and mortality all over the world. Due to an aging population, the incidence of stroke is rising significantly, which has led to devastating consequences for patients. In addition to traditional risk factors such as age, hypertension, hyperlipidemia, diabetes and atrial fibrillation, sleep disorders, as independent modifiable risk factors for stroke, have been highlighted increasingly. In this review, we provide an overview of common types of current sleep disturbances in cerebrovascular diseases, including insomnia, hypersomnia, breathing-related sleep disorders, and parasomnias. Moreover, evidence-based clinical therapeutic strategies and pitfalls of specific sleep disorders after stroke are discussed. We also review the neurobiological mechanisms of these treatments as well as their effects on stroke. Since depression after stroke is so prevalent and closely related to sleep disorders, treatments of post-stroke depression are also briefly mentioned in this review article.

Pharmacological evaluation of NO/cGMP/KATP channels pathway in the antidepressant-like effect of carbamazepine in mice

Carbamazepine, an anticonvulsant drug, has shown antidepressant effects in clinical and experimental models. Nitric oxide (NO) is a neurotransmitter in the central nervous system and has been involved in a variety of diseases including depression. In the present study, the involvement of NO/cyclic GMP/KATP channels pathway in the antidepressant action of carbamazepine was investigated in mice. The antidepressant-like activity was assessed in the forced swim test (FST) behavioral paradigm. Carbamazepine reduced (40 mg/kg, intraperitoneal) immobility period. The antidepressant-like effect of carbamazepine (40 mg/kg, intraperitoneal) was prevented by pretreatment with L-arginine [substrate for NO synthase (NOS), 750 mg/kg, intraperitoneal], sildenafil (a PDE-5 inhibitor, 5 mg/kg, intraperitoneal) and diazoxide (K+ channels opener, 10 mg/kg). Pretreatment of mice with L-NAME (a non-selective NOS inhibitor, 10 mg/kg, intraperitoneal), methylene blue (direct inhibitor of both NOS and soluble guanylate cyclase, 10 mg/kg, intraperitoneal) and glibenclamide (an ATP-sensitive K+ channel blocker, 1 mg/kg, intraperitoneal) produced potentiation of the action of a sub-effective dose of carbamazepine (30 mg/kg, intraperitoneal). Also, carbamazepine (30 mg/kg) potentiated the antidepressant-like effect of fluoxetine through NO modulation. The various modulators used in the study did not produce any changes in locomotor activity per se. The results demonstrated that the antidepressant-like effect of carbamazepine in the FST involved an interaction with the NO/cGMP/KATP channels pathway.

In vitro and in vivo regulation of synaptogenesis by the novel antidepressant spadin

BACKGROUND AND PURPOSE

We have described a novel antidepressant peptide, spadin, that acts by blocking the TWIK-related-potassium channel, type 1 (TREK-1). Here, we examined possible mechanisms of action of spadin at both molecular and cellular levels.

EXPERIMENTAL APPROACHES

Effects of spadin were measured in primary cultures of neurons or tissues from mice injected i.v. with spadin. Western blots, qPCR, histochemical and electrophysiological techniques were used.

KEY RESULTS

In vitro, spadin increased neuronal membrane potential and activated both the MAPK and PI3K signalling pathways, in a time- and concentration-dependent manner. The latter pathway was involved in the protective effect of spadin against staurosporine-induced apoptosis. Also, spadin enhanced both mRNA expression and protein of two markers of synaptogenesis, the post-synaptic density protein of 95 kDalton (PSD-95) and synapsin. We confirmed these effects on synaptogenesis by the observation that spadin treatment significantly increased the proportion of mature spines in cortical neurons. Finally, in vivo injections of spadin led to a rapid increase in both mRNA expression and protein level of brain-derived neurotrophic factor (BDNF) in the hippocampus, confirming the antidepressant action of the peptide. We argue for a new role of spadin in synaptogenesis as both PSD-95 and synapsin mRNA expression and protein levels were further enhanced in the hippocampus, following treatment in vivo with the peptide.

CONCLUSIONS AND IMPLICATIONS

These findings provide new mechanisms of action for the rapidly acting antidepressant peptide spadin by stimulating expression of BDNF and synaptic proteins, both in vitro and in vivo.

Mianserin as a discriminative stimulus in rats: asymmetrical cross-generalization with scopolamine

The present study was conducted to determine if the tetracyclic antidepressant mianserin could be established as a discriminative stimulus in rats. One group of rats was trained to discriminate mianserin (4.0 mg/kg, IP) from saline in a two-lever drug discrimination procedure, and a second group of rats was trained to discriminate the muscarinic cholinergic antagonist scopolamine (0.25 mg/kg, IP) from saline. Generalization testing with the training drugs yielded an ED50 of 0.502 mg/kg for the mianserin-trained rats and an ED50 of 0.048 mg/kg for the scopolamine-trained rats. Asymmetrical cross-generalization between mianserin and scopolamine was observed, because scopolamine produced mianserin-appropriate responding, but mianserin did not produce scopolamine-appropriate responding. This study is the first demonstration that rats can be trained to discriminate mianserin from saline and that antagonism of muscarinic cholinergic receptors is sufficient to produce mianserin-appropriate responding.

Sensitization to 5-HT1C receptor agonist in rats observed following withdrawal from chronic ethanol

Anxiogenic action of m-chlorophenylpiperazine (mCPP), a 5-HT1C receptor agonist, was studied in naive rats and in ethanol-tolerant rats following withdrawal from chronic ethanol administration. The purpose of this investigation was to determine whether a sensitization to mCPP develops during withdrawal from chronic ethanol. Male Long-Evans hooded rats were fed a liquid diet containing 4.5% ethanol or dextrin (as control) for four days. Twelve hours (acute withdrawal) or 4 days (protracted withdrawal) after the last dose of ethanol, rats were injected with saline or mCPP (0.08-5.0 mg/kg) and were tested in the elevated plus-maze 15 min postinjection. A reduction in percent open-arm activity, indicative of anxiogenic behavior, was observed in ethanol-treated rats injected with saline. Administration of mCPP further reduced the percent open-arm entries and time in ethanol-withdrawn rats. An eightfold reduction in maximum effective dose of mCPP was observed during acute ethanol withdrawal as compared to that in naive rats. During protracted ethanol withdrawal the maximum effective dose of mCPP was reduced by 75%. A shift of the mCPP dose-response curve to the left following withdrawal from chronic ethanol may indicate that 5-HT1C receptor sites are more sensitive to the activation by an agonist. This effect may be exploited in developing specific 5-HT1C receptor antagonists for the treatment of ethanol withdrawal symptoms.