title: Natriuretic peptide receptor-A is functionally expressed on bullfrog retinal Müller cells.
abstract: By the patch clamp technique, whole-cell currents induced by brain natriuretic peptide (BNP) from isolated bullfrog retinal Müller cells were studied. Application of 100 nM BNP induced a sustained inward current from these cells with a reversal potential of about 0 mV, and the current could be completely blocked by anantin, an antagonist of the A-type NP receptor (NPR-A) and CdCl(2), a blocker of cyclic nucleotide-gated (CNG) non-selective cation channels. Likewise, perfusion with the membrane-permeable cGMP analog 8-bromoguanosine-3',5'-cyclic monophosphate (8Br-cGMP) caused effects that are similar to those of BNP. Moreover, application of BNP failed to induce any current in the presence of 1 mM 8Br-cGMP. By calcium imaging, we further showed a significant increase in intracellular calcium levels ([Ca(2+)](i)) of all parts of Müller cells, including the endfoot, soma and processes following the perfusion of BNP, and the increase could be blocked by anantin. All these results suggest that NPR-A is expressed in bullfrog Müller cells, and activation of the receptor causes an increase of intracellular cGMP levels that activates CNG channels and thereby results in an increased calcium influx.
authors.affiliation: Institute of Neurobiology, Institutes of Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 20032, PR China.
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Cao
authors.forename: Xiong-Li
authors.initials: XL
authors.lastname: Yang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002469:Cell Separation; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003952:Diagnostic Imaging; D005456:Fluorescent Dyes; D016257:Fura-2; D007091:Image Processing, Computer-Assisted; D066298:In Vitro Techniques; D020097:Natriuretic Peptide, Brain / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010456:Peptides, Cyclic / Q000494:pharmacology; D011892:Rana catesbeiana; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D010456:Peptides, Cyclic; C058930:brain natriuretic peptide receptor; D020097:Natriuretic Peptide, Brain; C068090:anantin; C016276:8-bromocyclic GMP; D000242:Cyclic AMP; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP; D002118:Calcium; D016257:Fura-2