Atrial natriuretic factor inhibits ciliary motility in cultured rabbit tracheal epithelium

Abstract

To study the effect of atrial natriuretic factor (ANF) on airway ciliary motility, we measured ciliary beat frequency by a photoelectric method in response to ANF in cultured tracheal epithelial cells from rabbits. Addition of ANF but not [Tyr8]ANF-(5-27) decreased ciliary beat frequency in a dose-dependent fashion; the maximal decrease from the baseline value was 24.1 +/- 1.5% (+/- SE, P less than 0.001), and a half-maximal inhibitory concentration (IC50) was 3 x 10(-12) M. Inhibition of neutral endopeptidase activity by phosphoramidon (10(-6) M) or thiorphan (10(-6) M) potentiated the effect of ANF so that the dose-response curve for ANF was shifted to lower concentrations by approximately 0.5 log units (P less than 0.05, in each case). The inhibition of ciliary motility induced by ANF was not affected by the blockade of arachidonic acid metabolism with indomethacin, piroxicam, or nordihydroguaiaretic acid, but it was blocked by methylene blue, a soluble guanylate cyclase inhibitor, and was potentiated by M & B 22948, a guanosine 3',5'-cyclic monophosphate (cGMP) phosphodiesterase inhibitor. The intracellular cGMP levels were increased by ANF, an effect that was further potentiated by phosphoramidon or thiorphan. These results suggest that ANF inhibits ciliary motility presumably through a guanylate cyclase-dependent regulatory pathway and that neutral endopeptidase may play a role in modulating the ANF effect on airway mucociliary transport function.

The Effect of Cilia and the Mucociliary Clearance on Successful Drug Delivery

“…These substances including phosphorylation, cytoplasmic calcium, production of prostaglandins, nitric oxide and cGMP play an important role in ciliary beating. [83][84][85] Concurrent use of drugs such as non-steroidal anti-inflammatory drug (NSAID) drugs may have some effect on the mucociliary clearance through their inhibiting effect on the enzyme cyclooxygenase that regulates the arachidonic acid metabolism. Table 5 list up a formulation factors that affect the ciliary function, Table 6 a number of drugs and Table 7 a number of excipients.…”

Regulation of guanosine 3′:5′‐cyclic monophosphate in ovine tracheal epithelial cells

“…Human BNP 32 has been shown to be biologically active in other mammalian models (Takagi & Araki, 1992). The concentrations of natriuretic peptides required to elevate cyclic GMP (10 −5 m) were 10 and 10 fold greater than have previously been shown to be active in human cultured nasal epithelial cells (Geary et al , 1993) and rabbit tracheal epithelial cells (Tamaoki et al , 1991), respectively. Our results suggest that GC M is present in much smaller quantities than GC s in ovine tracheal epithelial cells.…”

“…Functional ANP receptors have previously been demonstrated by ultra‐cytochemical localization on rat bronchiolar epithelium (Rambotti & Sprecca, 1991). Tamaoki et al (1991) found that ANP increases cyclic GMP levels (approximately 2–3 fold increase) in rabbit cultured tracheal epithelial cells, but did not investigate the effect of other natriuretic peptides or NO donors. In human cultured nasal epithelial cells Geary et al (1993) found elevations in cellular cyclic GMP (approximately 30 fold increase) levels in response to SNP and CNP, but not ANP, BNP or STa toxin.…”

“…The effect of 5 × 10 −5 M lyophilized sheep haemoglobin which binds free NO (Gibson & Roughton, 1965) was studied on 10 −6 M SNP and 10 −5 M SNAP induced cyclic GMP production. The effect of 5 × 10 −4 M methylene blue, an inhibitor of guanylyl cyclase (Tamaoki et al , 1991) on cyclic GMP production induced by 10 −6 M SNP and 10 −5 M SNAP was also studied. Both the haemoglobin and methylene blue were pre‐in‐cubated with the cells for 30 min before the addition of SNP or SNAP.…”

“…Cyclic GMP regulate trans‐epithelial ion transport in kidney and colonic epithelial cells (Light et al , 1990; Argenzio & Armstrong, 1993) as well as increasing mucus secretion in gastric epithelial cells (Brown et al , 1993). Less is known about the role of cyclic GMP in airway epithelial physiology although studies in rabbit, human and bovine airway epithelia have suggested that natriuretic peptides and NO may regulate ciliary beat frequency (Tamaoki et al , 1991; Geary et al , 1995; Sisson 1995). Surprisingly, in view of the potential importance of cyclic GMP pathways in lung pathophysiology, no previous studies have comprehensively examined the regulation of this system in tracheal or bronchial epithelium.…”