Deletion of the M5 muscarinic acetylcholine receptor attenuates morphine reinforcement and withdrawal but not morphine analgesia

Little is known about the physiological roles of the M5 muscarinic receptor, the last member of the muscarinic receptor family (M1-M5) to be cloned. In the brain, the M5 receptor subtype is preferentially expressed by dopaminergic neurons of the substantia nigra and the ventral tegmental area. Dopaminergic neurons located in the ventral tegmental area are known to play important roles in mediating both the rewarding effects of opiates and other drugs of abuse and the manifestations of opiate/drug withdrawal symptoms. We therefore speculated that acetylcholine-dependent activation of M5 receptors might modulate the manifestations of opiate reward and withdrawal. This hypothesis was tested in a series of behavioral, biochemical, and neurochemical studies using M5 receptor-deficient mice (M5-/- mice) as novel experimental tools. We found that the rewarding effects of morphine, as measured in the conditioned place preference paradigm, were substantially reduced in M5-/- mice. Furthermore, both the somatic and affective components of naloxone-induced morphine withdrawal symptoms were significantly attenuated in M5-/- mice. In contrast, the analgesic efficacy of morphine and the development of tolerance to the analgesic effects of morphine remained unaltered by the lack of M5 receptors. The finding that M5 receptor activity modulates both morphine reward and withdrawal processes suggests that M5 receptors may represent a novel target for the treatment of opiate addiction.     

Hemoglobin A1c,frequency of glucose testing and social disadvantage: Metrics of racial health disparity in youth with type 1 diabetes

Introduction

Black youth with type 1 diabetes (T1D) have higher HbA1c than whites. To understand HbA1c differences, we examined the relationship of psycho-social factors and glucose testing with HbA1c.

Anesthesia and the developing brain: a way forward for clinical research

It is now well established that many general anesthetics have a variety of effects on the developing brain in animal models. In contrast, human cohort studies show mixed evidence for any association between neurobehavioural outcome and anesthesia exposure in early childhood. In spite of large volumes of research, it remains very unclear if the animal studies have any clinical relevance; or indeed how, or if, clinical practice needs to be altered. Answering these questions is of great importance given the huge numbers of young children exposed to general anesthetics. A recent meeting in Genoa brought together researchers and clinicians to map a path forward for future clinical studies. This paper describes these discussions and conclusions. It was agreed that there is a need for large, detailed, prospective, observational studies, and for carefully designed trials. It may be impossible to design or conduct a single study to completely exclude the possibility that anesthetics can, under certain circumstances, produce long‐term neurobehavioural changes in humans; however , observational studies will improve our understanding of which children are at greatest risk, and may also suggest potential underlying etiologies, and clinical trials will provide the strongest evidence to test the effectiveness of different strategies or anesthetic regimens with respect to better neurobehavioral outcome.     

Are acute exacerbations of chronic inflammatory appendicitis triggered by coprostasis and/or coproliths？

AIM- To examine the role of coprostasis and coproliths in recurrent appendicitis. METHODS： We evaluated four hundred and twenty seven consecutive pathology reports of all appendectomy specimens from January 2003 to December 2004. Findings were categorised as showing acute appendicitis, acute recurrent appendicitis, subacute recurrent appendicitis, chronic appendicitis, or appendices without inflammation. All patients had presented with acute right lower quadrant pain, In 94 instances, there was a history of recurrent similar episodes in the past. RESULTS： Of the 427 histology reports, 294 were inter- preted as showing acute appendicitis, 56 acute recurrent appendicitis, 34 subacute recurrent appen-dicitis, 28 chronic appendicitis, and 15 non-inflamed appendices. Coprostasis was observed in 58 patients （13.58%） and the presence of coprolith in 6 （1.4%）. Coprostasis, and age, were among the predictors in the final model. CONCLUSION： Coprostasis but not coproliths seems to be a contributing factor to acute exacerbations of chronic inflammatory appendicitis.