Cyclosomatostatin-induced catalepsy in the aged rat: a response to levodopa, diphenhydramine and nicotine

Sustainable Electrochemical Benzylic C-H Oxidation Using MeOH as an Oxygen Source

New methods and strategies for the direct oxidation of benzylic C-H bonds are highly desirable, owing to the importance of ketone motifs in significant organic transformations and the synthesis of valuable molecules, including pharmaceuticals, pesticides, and fine chemicals. Herein, we describe an electrochemical benzylic C-H oxidation strategy for the synthesis of ketones using MeOH as an oxygen source. Inexpensive and safe KBr serves as both an electrolyte and a bromide radical precursor in the reaction. This transformation also offers several advantages such as mild conditions, broad functional group tolerance, and operational simplicity. Mechanistic investigations by control experiments, radical scavenging experiments, electron paramagnetic resonance (EPR), kinetic studies, cyclic voltammetry (CV), and in-situ Fourier transform infrared (FTIR) spectroscopy support a pathway involving the formation and transformation of benzyl methyl ether via hydrogen atom transfer (HAT) and single-electron transfer (SET). The practical application of our strategy is highlighted by the successful synthesis of five pharmaceuticals, namely lenperone, melperone, diphenhydramine, cinnarizine, and flunarizine.

Cyclosomatostatin-induced catalepsy in aged rats: Specific change of brain c-Fos protein expression in the lateral entorhinal cortex

Aging represents the largest risk factor for developing Parkinson's disease (PD); another salient feature of this disorder is a decreased brain levels of somatostatin. Recently, in aged Wistar rats, we simulated the central somatostatinergic deficiency by intracerebroventricular injections of a somatostatin antagonist, cyclosomatostatin (cSST). The treated animals displayed catalepsy, a state that resembles the extrapyramidal signs of Parkinson's disease; young animals were insensitive to cSST. The neuroanatomical substrates responsible for the increased cataleptogenic activity of cSST in aged animals, are currently unknown. To study this issue, we assessed the cSST effect on brain c-Fos-protein expression in aged and young rats; thirty three brain regions were examined. cSST was employed at the dose cataleptogenic for aged animals and non-cataleptogenic for young ones. c-Fos expression patterns in the 'cataleptic' and 'non-cataleptic' animals were very similar, with the only distinction being a decrease in the c-Fos expression in the aged lateral entorhinal cortex (LEntCx). This decrease was not observed when the cSST-induced cataleptic response was inhibited by administration of diphenhydramine and nicotine. Thus, the development of catalepsy in the aged Wistar rats appeared to be associated with a hypoactivation of the LEntCx; possibly, there exists a mechanistic link between the LEntCx hypoactivation and increased susceptibility of aged rats to catalepsy. Apparently, these findings may provide novel insight into the link between mechanisms of parkinsonian motor disorders and aging.

Synergistic anticataleptic effect of imipramine and nicotine in a rotenone-induced rat model

RATIONALE

Some antidepressants have been previously found to produce anti-parkinsonian effect; nicotine was known to mitigate experimental neurotoxic lesions. The anticataleptic efficacy of antidepressant-nicotine co-administration is unstudied.

OBJECTIVES

This work aimed to evaluate anticataleptic action of imipramine-nicotine combination in rotenone model.

METHODS

Catalepsy was measured by the bar test. Concentrations of tyrosine hydroxylase, dopamine, and DOPAC were determined in the substantia nigra and dorsal striatum using ELISA and HPLC techniques; additionally, dopamine/DOPAC ratio was calculated for both areas.

RESULTS

Imipramine and nicotine alone were ineffective; however, co-administration of the drugs significantly (p < 0.01) inhibited rotenone-induced catalepsy and mitigated neurochemical changes in the nigrostriatal system. Anticataleptic effect of the combination exceeded that of levodopa, a standard drug for anti-parkinsonian treatment.

CONCLUSION

The combined use of imipramine and nicotine at relatively low doses inhibits neurotoxin-induced catalepsy and nigrostriatal neurochemical changes. The co-administration of these drugs might be a new approach to the treatment of extrapyramidal dysfunctions.