Bombesin-mediated calcium fluxes in myenteric plexus neurons.
Dual excitation microfluorimetry (Fura-2) was used to measure changes in intracellular calcium ([Ca2+]i) in individual cultured guinea pig myenteric neurons. Bombesin (5-500 nM) induced concentration-dependent increases in [Ca2+]i responses, with a maximal effect at 500 nM (56% of neurons responding, mean peak Ca2+ response 244 +/- 25 nM vs. basal 65 +/- 7 nM). Removal of Ca2+ from the median did not affect the initial [Ca2+]i peak but eliminated the subsequent plateau phase. The [Ca2+]i responses to bombesin was abolished by preincubation with thapsigargin (1 microM), a Ca(2+)-ATPase inhibitor (91 +/- 7% inhibition). [Ca2+]i responses to bombesin were inhibited by U73122 (1 microM), an inhibitor of phospholipase C (84 +/- 6% inhibition).
Department of Surgery, University of Michigan, Ann Arbor 48109, USA.
D M
DM
Simeone
B C
BC
Kimball
M W
MW
Mulholland
D000818:Animals; D000831:Animals, Newborn; D001839:Bombesin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004963:Estrenes / Q000494:pharmacology; D005470:Fluorometry; D006168:Guinea Pigs; D009197:Myenteric Plexus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology; D015398:Signal Transduction; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D004963:Estrenes; D010726:Phosphodiesterase Inhibitors; D011760:Pyrrolidinones; D013729:Terpenes; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D019284:Thapsigargin; D010738:Type C Phospholipases; D000252:Calcium-Transporting ATPases; D001839:Bombesin; D002118:Calcium