1. A peptide derivative represented by the following formula (1) or a salt thereof;
1
, wherein R
1
is hydrogen atom or methyl group, R
2
is hydrogen atom or hydroxy group and n is an integer of 1-8, provided that R
1
is hydrogen atom when R
2
is hydrogen atom, which has specific and high binding affinity with the &mgr;-opioid receptor.
1.下式(1)所代表的
多肽衍
生物或其盐;
1
其中 R
1
是氢原子或甲基,R
2
是氢原子或羟基,n 是 1-8 的整数,条件是 R
1
为氢原子时,R
2
为氢原子时,R 1 为氢原子,它与 &mgr;-阿片受体具有特异性和高结合亲和力。