BETA-ENDORPHIN - INTERACTION OF SYNTHETIC ANALOGS HAVING DIFFERENT CHAIN LENGTHS WITH MORPHINE AND ENKEPHALIN RECEPTORS IN RAT-BRAIN MEMBRANES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 19  (3) , 259-262
Abstract
Human .beta.-endorphin [.beta.-EP] analogs [.beta.-EP 1-31, .beta.-EP 1-30, .beta.-EP 1-29, .beta.-EP 1-28, .beta.-EP 1-27, .beta.-EP 1-26, .beta.-EP 1-21, .beta.-EP 1-15, .beta.-EP 1-5] with various chain lengths were investigated for their potency in displacing tritiated dihydromorphine and Leu-enkephalin binding in rat brain membrane preparations. The reduction of chain length from residues 1-31 to 1-5 led to a gradual loss of preference for the morphined receptor. The extension of the chain length of the Met-enkephalin segment to the COOH-terminal glutamic acid modified the binding of the NH2-terminal sequence to the enkephali receptor. The fact that camel .beta.-endorphin is more potent in displacing the 2 tritiated primary ligands than the human hormone is also reported herein.