ABSTRACT
Objective:To assess the effects of ohmefentanyl(OMF),a potent and selective agonist for ? opiate receptor,on respiratory function in chronic hypoxic rats.Methods:Totally 86 healthy male SD rats were randomly divided into the normal group ( n =20) and chronic hypoxic model group( n =66).The chronic hypoxic rat model was established by intravenous injections of papain once a week for 6 times.Rats in normal control group received OMF injection( n =10) and artificial cerebrospinal fluid(aCSF) injection( n =10).Rats in chronic hypoxic group were further divided into cerebroventricular administration group( n =48) and nucleus tractus solitari(NTS) administration group( n =18).Rats in cerebroventricular administration group received naloxone( n =12) and OMF( n =12),and the other 24 rats were taken as control.Rats in NTS group received OMF( n =9) and aCSF( n =9).The respiratory rate(RR) and tidal volume(V T) were determined 5,15,30,45 and 60 min after injection.Results:Intracerebroventricular administration of OMF in normal rats resulted in a significant decrease in RR and V T ( P