The endocannabinoid system within the dorsal lateral geniculate nucleus of the vervet monkey.

The endocannabinoid system mainly consists of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), their endogenous ligands termed endocannabinoids (eCBs), and the enzymes responsible for the synthesis and degradation of eCBs. These cannabinoid receptors have been well characterized in rodent and monkey retinae. Here, we investigated the expression and localization of the eCB system beyond the retina, namely the first thalamic relay, the dorsal lateral geniculate nucleus (dLGN), of vervet monkeys using immunohistochemistry methods. Our results show that CB1R is expressed throughout the dLGN with more prominent labeling in the magnocellular layers. The same pattern is observed for the degradation enzyme, fatty acid amide hydrolase (FAAH). However, the synthesizing enzyme N-acyl-phosphatidylethanolamine phospholipase D (NAPE-PLD) is expressed homogenously throughout the dLGN with no preference for any of the layers. These proteins are weakly expressed in the koniocellular layers. These results suggest that the presence of the eCB system throughout the layers of the dLGN may represent a novel site of neuromodulatory action in normal vision. The larger amount of CB1R in the dLGN magnocellular layers may explain some of the behavioral effects of cannabinoids associated with the integrity of the dorsal visual pathway that plays a role in visual-spatial localization and motion perception.

Comparison of cardiopulmonary variables with intermittent positive pressure ventilation and high-frequency jet ventilation during abdominal aortic operations.

Cardiopulmonary variables with intermittent positive pressure ventilation (IPPV) and high-frequency jet ventilation (HFJV) were compared in 8 patients undergoing elective abdominal aortic operations under fentanyl-nitrous oxide anesthesia. Hemodynamics were stable under the two methods of ventilation, and most of the corresponding hemodynamic variables were statistically indifferent from each other. Alveolar gas exchange was also adequate with either method and most of the corresponding respiratory variables were not statistically different. The peak airway pressure was significantly less during HFJV than during IPPV (p less than 0.01). Diaphragmatic excursions are less during HFJV than during IPPV, resulting in a quieter surgical field. Therefore, hemodynamic stability and gas exchange adequacy coupled with less diaphragmatic excursions and lower peak airway pressure make HFJV an acceptable alternative to IPPV during abdominal aortic operations.