title: Calcium regulation of ciliary beat frequency in human respiratory epithelium in vitro.
abstract: 1. The changes in ciliary beat frequency (CBF) of human nasal respiratory epithelial cells were measured in vitro with a photometric technique following exposure to either 4-bromo-calcium ionophore A23187 (4-Br-A23187) or trifluoperazine (TFP), an inhibitor of calmodulin-sensitive calcium-dependent protein kinases. Changes in intracellular free calcium concentrations in response to 4-Br-A23187 were studied using a fluorescent dye (Fura-2). 2. Addition of 10(-5) M-4-Br-A23187 caused a time-dependent (P less than 0.01) rise in CBF. The increment in CBF was statistically significant 10 min after challenge (+10%; P less than 0.01) and was sustained for at least 1 h, with maximal stimulation after 40 min (+ 18%; P less than 0.01). 3. Exposure to 10(-5) M-4-Br-A23187 caused an immediate increase in intracellular free calcium concentration, which preceded the rise in CBF. 4. TFP (10(-4) M) caused a reduction of baseline CBF (-10%; P less than 0.01) and prevented the expected rise when the cells were subsequently exposed to 10(-5) M-4-Br-A23187. 5. We conclude that: (1) calcium ionophore stimulates the CBF of human respiratory cells; (2) this effect is mediated through a calmodulin-sensitive system, since it is abolished in the presence of TFP; (3) the same pathway appears to control the basal CBF of these cells, since TFP also decreases CBF.
authors.affiliation: Department of Medicine, Faculty of Clinical Sciences, University College, London.
authors.forename: G
authors.initials: G
authors.lastname: Di Benedetto
authors.forename: C J
authors.initials: CJ
authors.lastname: Magnus
authors.forename: P T
authors.initials: PT
authors.lastname: Gray
authors.forename: A
authors.initials: A
authors.lastname: Mehta
mesh_terms: D000293:Adolescent; D000328:Adult; D000001:Calcimycin / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000032:analysis / Q000502:physiology*; D002923:Cilia / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000737:chemistry / Q000502:physiology*; D013997:Time Factors; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D014268:Trifluoperazine; D000001:Calcimycin; C033170:4-bromo-A-23187; D002118:Calcium