A study done by ClemsonUniversity in South Carolina showedthat opioid hormones may be relatedto changes in both blood pressure(BP) and sensitivity to pain in patientswith early-stage hypertension. Theresults of the study were published inthe January/February 2006 issue ofthe medical journal PsychosomaticMedicine.
According to researchers, patientswith hypertension have reduced painsensitivity, which also appears inyoung people at risk for hypertension.They suggest that altered sensitivityto pain may be a part of the earlydevelopment of hypertension. Theexact relationship between the 2 conditionsis not clear, however.
Researchers studied the effects ofnatural opioids, such as endorphins andenkephalins, on pain perception and BPin 125 young adults with mildly elevatedBP. On different occasions, participantswere given the opioid blocker naltrexoneor placebo 60 minutes beforetheir pain threshold was tested byimmersing their hands in ice water for 2minutes or as long as they could bear.The results showed that BP rises assensitivity to pain drops, whether or notnatural opioids are blocked. This findingindicates "a greater degree of opioidanalgesic tone in young persons at riskfor hypertension," the researchers said.