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▽ E Phe 4 ‐enkephalin analogs Delta receptors in rat brain are different from those in mouse vas deferens
Author(s) -
Shimohigashi Yasuyuki,
Costa Tommaso,
Pfeiffer Andreas,
Herz Albert,
Kimura Hitoshi,
Stammer Charles H.
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80193-x
Subject(s) - vas deferens , enkephalin , receptor , chemistry , medicine , endocrinology , stereochemistry , μ opioid receptor , guinea pig , biology , biochemistry , opioid
Conformationally restricted enkephalin analogs containing E ‐cyclopropylphenylalanine (▽ E Phe), [D‐Ala 2 , (2 R ,3 S )‐▽ E Phe 4 ,Leu 5 ]enkephalin and its (2 S ,3 R ) isomer, were evaluated in receptor‐binding assays using rat brain and in assays using muscle preparations. The (2 S ,3 R ) isomer was almost completely inactive in all assays. In contrast, the (2 R ,3 S ) isomer showed a very high affinity for the δ and a very weak affinity for the μ receptors in rat brain. The extent of δ affinity and the selectivity of this isomer were almost equal to those of [D‐Pen 2 ,D‐Pen 5 ]enkephalin. However, the (2 R ,3 S ) isomer was inactive in both the mouse vas deferens and guinea pig ileum assays, and showed no antagonistic activity in these tissues. These results indicate that the (2 R ,3 S ) isomer interacts with the δ receptors in rat brain, but not with those in the mouse vas deferens, and they suggest that the δ receptors in the central and peripheral nervous systems are different from each other.