The Journal of pharmacology and experimental therapeutics
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J. Pharmacol. Exp. Ther. · Jan 2018
An Approach to Discovering Novel Muscarinic M1 Receptor Positive Allosteric Modulators with Potent Cognitive Improvement and Minimized Gastrointestinal Dysfunction.
Activation of muscarinic M1 receptor (M1R) is a promising approach for improving cognitive impairment in Alzheimer's disease. However, an M1R-selective positive allosteric modulator (PAM), benzyl quinolone carboxylic acid (BQCA), at 30 mg/kg, induced diarrhea in wild-type mice, but not in M1R knockout mice. Moreover, BQCA (0.1-1000 nM) augmented electric field stimulation (EFS)-induced ileum contraction in an in vitro Magnus assay. ⋯ Compound A, at 30 mg/kg, significantly improved scopolamine-induced cognitive deficits without prominent signs of diarrhea at up to 1000 mg/kg in mice. In contrast, compound B, at 10 mg/kg, showed both significant improvement of scopolamine-induced cognitive deficits and severe diarrhea. Thus, fine adjustment of the α-values could be a key to discovering M1 PAMs yielding potent cognitive improvement with a lower risk of GI effects.
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J. Pharmacol. Exp. Ther. · Jan 2018
Nicotine Prevents and Reverses Paclitaxel-Induced Mechanical Allodynia in a Mouse Model of CIPN.
Chemotherapy-induced peripheral neuropathy (CIPN), a consequence of peripheral nerve fiber dysfunction or degeneration, continues to be a dose-limiting and debilitating side effect during and/or after cancer chemotherapy. Paclitaxel, a taxane commonly used to treat breast, lung, and ovarian cancers, causes CIPN in 59-78% of cancer patients. Novel interventions are needed due to the current lack of effective CIPN treatments. ⋯ Notably, nicotine neither promoted proliferation of A549 and H460 non-small cell lung cancer cells nor interfered with paclitaxel-induced antitumor effects, including apoptosis. Most importantly, chronic nicotine administration did not enhance Lewis lung carcinoma tumor growth in C57BL/6J mice. These data suggest that the nicotinic acetylcholine receptor-mediated pathways may be promising drug targets for the prevention and treatment of CIPN.