Endocannabinoid system modulates relapse to methamphetamine seeking: possible mediation by the arachidonic acid cascade.

We clarified the modulating action of the endocannabinoid system, and its possible mediation by the arachidonic acid cascade, on the reinstatement of methamphetamine (METH)-seeking behavior, using the intravenous self-administration paradigm in rats. Following 12 days of self-administration of METH, the replacement of METH with saline resulted in a gradual decrease in lever press responses (extinction). Under extinction conditions, METH-priming or re-exposure to cues previously paired with METH infusion markedly increased the responses (reinstatement of drug-seeking). The cannabinoid CB1 receptor antagonist, SR141716A, blocked this behavior. Although the cannabinoid agonist, Delta8-tetrahydrocannabinol (THC), had no effects by itself, coadministration of the agonist and METH at small doses reinstated the drug-seeking behavior. THC attenuated the effects of the reinstatement-inducing dose of METH, but enhanced the effect of cues. Either given repeatedly during the extinction or singly, 24 h before the first METH-priming or cues challenge, THC suppressed the reinstatement. In another set of experiments, we found that diclofenac, a cyclooxygenase inhibitor, also attenuated the reinstatement induced by exposure to cues or drug-priming. These results suggest that the endocannabinoid system, through possible mediation by the arachidonic acid cascade, serves as a modulator of the reinstating effects of METH-priming and cues. Extending the current view on the treatment of drug dependence, these results indicate that endocannabinoid-activating substances as well as cyclooxygenase inhibitors may be promising as antirelapse agents.     

Prevalence and viral DNA loads of three novel human polyomaviruses in skin cancers from Japanese patients

Merkel cell polyomavirus (MCPyV), human polyomaviruses 6 (HPyV6) and 7 (HPyV7) are novel human polyomaviruses. This study investigated their detection rates and DNA loads in various skin cancers from Japanese patients. MCPyV, HPyV6 and HPyV7 were detected in 22.2%, 3.2% and 1.6% of squamous cell carcinomas, 18.0%, 2.0% and 4.0% of basal cell carcinomas, and 19.1%, 4.3% and 4.3% of melanomas, respectively. Quantitative real‐time polymerase chain reaction showed that their DNA loads were low. These findings provide the first evidence of the prevalence of HPyV6 and HPyV7 in skin cancers in Asia. Nucleotide differences were found in the large T‐sequenced region between Japanese and North American isolates: a nucleotide substitution of A to G for HPyV6; and a nucleotide substitution of T to C and the insertion of a gap for HPyV7. This suggested that two genotypes of HPyV6 and HPyV7 would be present and associated with geographical origin.     

Correction to: The characteristics of gastrointestinal symptoms in patients with severe COVID-19: a systematic review and meta-analysis

Journal of Gastroenterology - A correction to this paper has been published: https://doi.org/10.1007/s00535-021-01786-z