title: Calmodulin content in rabbit reticulocyte and the influence of opioid peptides on calmodulin activity in its membrane.
abstract: Calmodulin (CaM) content in rabbit reticulocyte and the influence of opioid peptides on CaM activity in its membrane were studied by a highly sensitive assay of CaM activity based on the stimulation of Calcium-dependent phosphodiesterase activity. The CaM contents in reticulocytes were higher than those in normal erythrocytes, both in the cytosol fraction and in the membrane fraction. Among the opioid peptides, beta-endorphin (beta-EP) and dynorphin-A-(1-13) (dyn) had a significant inhibitory effect on CaM activity in reticulocyte membrane. The effect was not antagonized by naloxone or Mr. 2266, nor influenced by increase of Ca2+ concentration, but was reversed by the addition of exogenous CaM. This implies that the action of beta-EP and dyn on reticulocyte membranes probably involves an non-opioid mechanism, in which CaM may be an important key of linkage.
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000097:blood*; D004399:Dynorphins / Q000494:pharmacology; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D011817:Rabbits; D012156:Reticulocytes / Q000187:drug effects / Q000378:metabolism*; D001615:beta-Endorphin / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D004723:Endorphins; D010446:Peptide Fragments; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; C026843:dynorphin (1-13); D004399:Dynorphins