title: Interstitial cell modulation of pyeloureteric peristalsis in the mouse renal pelvis examined using FIBSEM tomography and calcium indicators.
abstract: Typical and atypical smooth muscle cells (TSMCs and ASMCs, respectively) and interstitial cells (ICs) within the pacemaker region of the mouse renal pelvis were examined using focused ion beam scanning electron (FIB SEM) tomography, immunohistochemistry and Ca2+imaging. Individual cells within 500-900 electron micrograph stacks were volume rendered and associations with their neighbours established. 'Ribbon-shaped', Ano1 Cl-channel immuno-reactive ICs were present in the adventitia and the sub-urothelial space adjacent to the TSMC layer. ICs in the proximal renal pelvis were immuno-reactive to antibodies for CaV3.1 and hyperpolarization-activated cation nucleotide-gated isoform 3 (HCN3) channel sub-units, while basal-epithelial cells (BECs) were intensely immuno-reactive to Kv7.5 channel antibodies. Adventitial to the TSMC layer, ASMCs formed close appositions with TSMCs and ICs. The T-type Ca2+channel blocker, Ni2+(10-200 μM), reduced the frequency while the L-type Ca2+channel blocker (1 μM nifedipine) reduced the amplitude of propagating Ca2+waves and contractions in the TSMC layer. Upon complete suppression of Ca2+entry through TSMC Ca2+channels, ASMCs displayed high-frequency (6 min-1) Ca2+transients, and ICs distributed into two populations of cells firing at 1 and 3 min-1, respectively. IC Ca2+transients periodically (every 3-5 min-1) summed into bursts which doubled the frequency of ASMC Ca2+transient firing. Synchronized IC bursting and the acceleration of ASMC firing were inhibited upon blockade of HCN channels with ZD7288 or cell-to-cell coupling with carbenoxolone. While ASMCs appear to be the primary pacemaker driving pyeloureteric peristalsis, it was concluded that sub-urothelial HCN3(+), CaV3.1(+) ICs can accelerate ASMC Ca2+signalling.
authors.affiliation: Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan.
authors.forename: Hikaru
authors.initials: H
authors.lastname: Hashitani
authors.affiliation: Department of Pharmacology, School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Nguyen
authors.affiliation: Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Noda
authors.affiliation: Department of Cell Physiology, Nagoya City University Graduate School of Medical Sciences, Nagoya, 467-8601, Japan.
authors.forename: Retsu
authors.initials: R
authors.lastname: Mitsui
authors.affiliation: Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Ryuhei
authors.initials: R
authors.lastname: Higashi
authors.affiliation: Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Anatomy, Kurume University School of Medicine, Kurume, Japan.
authors.forename: Kei-Ichiro
authors.initials: KI
authors.lastname: Nakamura
authors.affiliation: Department of Pharmacology, School of Biomedical Sciences, Monash University, Clayton, VIC, 3800, Australia. rick.lang@monash.edu.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Lang
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling; D055032:Electron Microscope Tomography; D005260:Female; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels / Q000378:metabolism; D056885:Interstitial Cells of Cajal / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D010528:Peristalsis; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism; D014551:Urinary Tract / Q000378:metabolism / Q000648:ultrastructure; D014553:Urinary Tract Physiological Phenomena
chemical_list: D015220:Calcium Channels; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D024642:Potassium Channels, Voltage-Gated
keywords: Calcium; Focused ion bean scanning electron microscopy; Pyeloureteric peristalsis; Smooth muscle cells; Upper urinary tract