title: Opiate analgesics and endorphins inhibit rat dorsal root potential in vitro.
abstract: The effects of endorphins and opiate analgesics on the dorsal root potential (DRP) were studied in vitro using the isolated spinal cord of newborn rat. Bath-applied beta-endorphin and [D-Ala2]-Met-enkephalinamide (D-Ala) greatly depressed the DRP and the depressant effects were abolished by prior perfusion with naloxone. The potency of Met-enkephalin, Leu-enkephalin and alpha-endorphin was much weaker than that of D-Ala. Morphine and levorphanol depressed the DRP and these effects were also antagonized by naloxone. The isolated rat spinal cord appears to be a convenient in vitro preparation for analysing the effects of opiates on synaptic transmission in the central nervous system.
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D051381:Rats; D013116:Spinal Cord / Q000187:drug effects*; D013126:Spinal Nerve Roots / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D018822:alpha-Endorphin; D001615:beta-Endorphin
chemical_list: D000701:Analgesics, Opioid; D004723:Endorphins; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; C013801:enkephalin-Met, Ala(2)-; D018822:alpha-Endorphin