TY - JOUR
T1 - Secretagogue-induced changes in membrane calcium permeability in chicken and chinchilla ileal mucosa. Selective inhibition by loperamide
AU - Chang, E. B.
AU - Brown, D. R.
AU - Wanf, N. S.
AU - Field, M.
PY - 1986
Y1 - 1986
N2 - Substance P (SP), neurotensin (NT), bombesin (BB), serotonin (5HT), and carbamylcholine (CCH) transiently increase electrogenic anion secretion in chinchilla and chicken ileum. SP and CCH also transiently inhibit amiloride-sensitive Na/H exchange in isolated chicken enterocytes. Loperamide (LP) inhibits the short-circuit responses caused by SP, NT, and BB, but not those caused by CCH, 5HT, Ca ionophore, or cyclic nucleotides. Similarly, LP inhibits the effects of SP, but not those of CCH, on Na/H exchange. LP inhibition of the SP effects was further studied in isolated chicken enterocytes. CCH and SP transiently increased cytosolic Ca activity by 20-50 nmol/liter, but only the response to SP was inhibited by LP (10-5 M) and by the absence of extracellular Ca. We conclude (a) SP and CCH effects on intestinal electrolyte transport are mediated by increasing enterocyte Ca activity and (b) LP specifically inhibits peptide hormone-activated Ca entry by an opiate receptor-independent mechanism.
AB - Substance P (SP), neurotensin (NT), bombesin (BB), serotonin (5HT), and carbamylcholine (CCH) transiently increase electrogenic anion secretion in chinchilla and chicken ileum. SP and CCH also transiently inhibit amiloride-sensitive Na/H exchange in isolated chicken enterocytes. Loperamide (LP) inhibits the short-circuit responses caused by SP, NT, and BB, but not those caused by CCH, 5HT, Ca ionophore, or cyclic nucleotides. Similarly, LP inhibits the effects of SP, but not those of CCH, on Na/H exchange. LP inhibition of the SP effects was further studied in isolated chicken enterocytes. CCH and SP transiently increased cytosolic Ca activity by 20-50 nmol/liter, but only the response to SP was inhibited by LP (10-5 M) and by the absence of extracellular Ca. We conclude (a) SP and CCH effects on intestinal electrolyte transport are mediated by increasing enterocyte Ca activity and (b) LP specifically inhibits peptide hormone-activated Ca entry by an opiate receptor-independent mechanism.
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U2 - 10.1172/JCI112562
DO - 10.1172/JCI112562
M3 - Article
C2 - 2424933
AN - SCOPUS:0022472805
SN - 0021-9738
VL - 78
SP - 281
EP - 287
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
IS - 1
ER -