A pivotal role for cADPR-mediated Ca2+ signaling: regulation of endothelin-induced contraction in peritubular smooth muscle cells.
cADPR, a potent calcium-mobilizing intracellular messenger synthesized by ADP-ribosyl cyclases regulates openings of ryanodine receptors (RyR). Here we report that in the rat testis, a functional cADPR Ca2+ release system is essential for the contractile response of peritubular smooth muscle cells (PSMC) to endothelin (ET). We previously showed that this potent smooth muscle agonist elicits intracellular Ca2+ release in PSMC and seminiferous tubule contraction via activation of ETA and ETB receptors. ETB-R induces the mobilization of a thapsigargin-sensitive but IP3-independent intracellular Ca2+ pool. Stimulation of permeabilized PSMC with cADPR was found to elicit large Ca2+ releases blocked by either a selective antagonist of cADPR or a RyR blocker, but not by heparin. Western blotting and confocal fluorescence microscopy indicated the specific expression of type 2 RyR in perinuclear localization. ET was found to stimulate the activity of ADP-ribosyl cyclase. Microinjection of the selective cADPR antagonist 8NH2-cADPR completely abolished subsequent stimulation of Ca2+ signaling via ETA and ETB receptors. cADPR therefore appears to have an obligatory role for ETA-R and ETB-R-mediated calcium signaling in PSMC. However, ETB-R seem to be coupled exclusively to cADPR whereas ETA-R activation may be linked to IP3 and cADPR signaling pathways.
Barone
Fortunata
F
Istituto Pasteur Fondazione Cenci Bolognetti, Department of Histology and Medical Embryology, University of Rome La Sapienza, 00161 Rome, Italy.
Genazzani
Armando A
AA
Conti
Antonio
A
Churchill
Grant C
GC
Palombi
Fioretta
F
Ziparo
Elio
E
Sorrentino
Vincenzo
V
Galione
Antony
A
Filippini
Antonio
A
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000378:metabolism; D015153:Blotting, Western; D001896:Boron Compounds / Q000737:chemistry; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D046508:Culture Techniques; D036563:Cyclic ADP-Ribose; D019332:Endothelin-1 / Q000494:pharmacology*; D016232:Endothelins / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000737:chemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008297:Male; D008562:Membrane Glycoproteins; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D009244:NAD+ Nucleosidase / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D051381:Rats; D044023:Receptor, Endothelin B; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D017466:Receptors, Endothelin / Q000819:agonists; D012433:Ryanodine / Q000378:metabolism / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000032:analysis; D012671:Seminiferous Tubules / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure
C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D015703:Antigens, CD; D000943:Antigens, Differentiation; D001896:Boron Compounds; D015220:Calcium Channels; D019332:Endothelin-1; D016232:Endothelins; D005456:Fluorescent Dyes; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D044023:Receptor, Endothelin B; D018160:Receptors, Cytoplasmic and Nuclear; D017466:Receptors, Endothelin; D019837:Ryanodine Receptor Calcium Release Channel; D036563:Cyclic ADP-Ribose; C074308:sovateltide; D012433:Ryanodine; D000246:Adenosine Diphosphate Ribose; D036541:ADP-ribosyl Cyclase; C498156:Cd38 protein, rat; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1