The purpose of this study was to investigate the effects of α₂ adrenergic receptor agonist dexmedetomidine on withdrawal symptoms in alcohol-dependent rats and the underlying mechanism, so as to provide a scientific basis for the treatment of alcohol withdrawal syndrome (AWS). Adult Sprague-Dawley (SD) male rats were orally administered with 6% aqueous alcohol continuously for 28 d to establish alcohol drinking model, and then stopped drinking to induce AWS. Enzyme-linked immunosorbent assay (ELISA) was used to determine the content of norepinephrine (NE) in the locus coeruleus and hippocampus of rats. Dexmedetomidine (5, 10, and 20 μg/kg) was intraperitoneally injected respectively when the rats showed significant AWS. In some rats, α₂ adrenergic receptor antagonist yohimbine was injected into hippocampus in advance. The results showed that, compared with the control group, the 6 h withdrawal group exhibited significantly increased AWS score and amount of repeat drinking. The NE contents in hippocampus and locus coeruleus of the last drinking and the 6 h withdrawal groups were significantly increased compared with those of the control group. Dexmedetomidine intervention significantly decreased AWS score and hippocampus NE content in the 6 h withdrawal group, while yohimbine could reverse these effects of dexmedetomidine. These results suggest that dexmedetomidine might improve the withdrawal symptoms in alcohol-dependent rats via activating α₂ adrenergic receptor.
Adrenergic alpha-2 Receptor Agonists/therapeutic use* ; Alcoholism/drug therapy* ; Animals ; Dexmedetomidine/therapeutic use* ; Hippocampus/metabolism* ; Male ; Norepinephrine ; Rats ; Rats, Sprague-Dawley ; Receptors, Adrenergic, alpha-2/metabolism* ; Substance Withdrawal Syndrome/drug therapy* ; Yohimbine/pharmacology*

We report five cases of non-arteritic anterior ischaemic optic neuropathy (NA-AION) where spontaneous resolution of the optic disc swelling occurred, and all relevant visual modalities were normal at presentation and remained so until resolution of the process after a median time of 9.6 weeks. This condition, which can be termed 'incipient NA‑AION' or 'threatened NA-AION', should be recognised so that unnecessary investigations for other and more serious causes of optic disc swelling can be prevented.
Adrenergic alpha-2 Receptor Agonists ; therapeutic use ; Adult ; Brimonidine Tartrate ; therapeutic use ; Diagnosis, Differential ; Female ; Humans ; Male ; Middle Aged ; Ophthalmic Solutions ; Optic Disk ; pathology ; Optic Neuropathy, Ischemic ; diagnosis ; Singapore ; Time Factors ; Vision, Ocular ; Visual Acuity