Muscular rigidity caused by opioids is due to the agonistic effect on which receptor?
Ans. (A) Mu(Ref: Miller 7th/e p781)Truncal rigidity caused by highly lipid soluble opioids like fentanyl is supraspinal in origin. It is mainly caused by stimulation of mu receptors whereas kappa and delta receptors tend to reduce the rigidity.
Mu
Kappa
Delta
Sigma
Anaesthesia