Chronic intrathecal cannulation affects hypothalamic opioids depending on the technique employed.

Previous studies have shown that chronic intrathecal cannulation can interfere with the homeostasis of central opioid peptides. These results show that beta-endorphin and Met-enkephalin concentrations did not change in the hypothalamus of rats bearing a chronic cannula inserted between C8-T1 up to L3 and fixed to the processes transversus T1. These results suggest that chronically cannulated rats can be considered as normal when studying hypothalamic beta-endorphin or Met-enkephalin concentrations, and used in physiological studies, depending on the technique employed.