title: The calcium receptor modulates the hyperpolarization-activated current in subfornical organ neurons.
abstract: Here we report that neurons of the subfornical organ (SFO), a circumventricular structure devoid of a blood-brain barrier, show time-dependent, inward rectification indicative of the presence of a subthreshold, hyperpolarization-activated inward current (Ih). In whole-cell patch clamp experiments of isolated SFO neurons, we observed a Cs+-sensitive Ih in 47% of cells tested. Furthermore, we show that Ih is involved in the generation of evoked bursts in SFO neurons. An allosteric agonist of the extracellular calcium-sensing receptor (CaR) was found to potentiate Ih consistent with our previous observations of CaR-mediated bursting in SFO neurons. These studies indicate that a proportion of SFO neurons express Ih, and this may be one ionic mechanism through which bursting is regulated by various extracellular messengers.
authors.affiliation: Department of Physiology, Queen's University, Kingston, ON, Canada.
authors.forename: D L
authors.initials: DL
authors.lastname: Washburn
authors.forename: J W
authors.initials: JW
authors.lastname: Anderson
authors.forename: A V
authors.initials: AV
authors.lastname: Ferguson
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000819:agonists / Q000378:metabolism*; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002586:Cesium / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013356:Subfornical Organ / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020960:omega-Conotoxins / Q000494:pharmacology
chemical_list: D000814:Aniline Compounds; D002135:Calcium-Binding Proteins; D007473:Ion Channels; C111654:NPS R-467; D020960:omega-Conotoxins; D002586:Cesium