title: Effects of chemostimuli on [Ca2+]i responses of rat aortic body type I cells and endogenous local neurons: comparison with carotid body cells.
abstract: Mammalian aortic bodies (ABs) are putative peripheral arterial chemoreceptors whose function remains controversial, partly because information on their cellular physiology is lacking. In this study, we used ratiometric Ca2+ imaging to investigate for the first time chemosensitivity in short-term cultures of dissociated cells of juvenile rat ABs, located near the junction of the left vagus and recurrent laryngeal nerves. Among the surviving cell population were glomus or type I cell clusters, endogenous local neurons and glia-like cells. A variety of chemostimuli, including hypoxia, isohydric or acidic hypercapnia, and isocapnic acidosis, caused a rise in intracellular [Ca2+] in AB type I cells. The [Ca2+]i responses were indistinguishable from those in carotid body (CB) type I cells grown in parallel cultures from the same animals, and responses to acidic hypercapnia were prevented by the non-specific voltage-gated Ca2+ channel antagonist, 2mM Ni2+. Furthermore, we identified a subpopulation (∼40%) of glia-like cells in AB cultures that resembled CB type II cells based on their approximately equal sensitivity to ATP and UTP, consistent with the expression of purinergic P2Y2 receptors. Finally, we showed that some local neurons, known to be uniquely associated with these AB paraganglia in situ, generated robust [Ca2+]i responses to these chemostimuli. Thus, these AB type I cells and associated putative type II cells resemble those from the well-studied CB. Unlike the CB, however, they also associate with a special group of endogenous neurons which we propose may subserve a sensory function in local cardiovascular reflexes.
authors.affiliation: Department of Biology, McMaster University, Life Sciences Building, Hamilton, Ontario, Canada. piskurn@mcmaster.ca
authors.forename: Nikol A
authors.initials: NA
authors.lastname: Piskuric
authors.forename: Colin A
authors.initials: CA
authors.lastname: Nurse
mesh_terms: D000138:Acidosis / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001016:Aortic Bodies / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002344:Carotid Body / Q000187:drug effects / Q000378:metabolism*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D058473:Receptors, Purinergic P2Y2 / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D014544:Uridine Triphosphate / Q000378:metabolism
chemical_list: D002121:Calcium Channel Blockers; D058473:Receptors, Purinergic P2Y2; D000255:Adenosine Triphosphate; D010100:Oxygen; D002118:Calcium; D014544:Uridine Triphosphate