title: beta-Endorphin: development of tolerance and its reversal by 5-hydroxytryptophan in cats.
abstract: Tolerance to beta-endorphin developed acutely in cats if the administration of the peptide was repeated within the first 24 hr. The tolerance was reversed immediately by systemic administration of the serotonin precursor, 5-hydroxytryptophan. It was further shown that 5-hydroxytryptophan potentiates the analgesic effect of the subliminal dose of beta-endorphin.
mesh_terms: D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000698:Analgesia; D000818:Animals; D002415:Cats; D004361:Drug Tolerance; D004723:Endorphins / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology
chemical_list: D004723:Endorphins; D009270:Naloxone; D006916:5-Hydroxytryptophan