Effect of atrial natriuretic factor (ANF) on nicotinic acetylcholine receptor channels in bovine chromaffin cells

Abstract

Abstract. Bovine chromaffin cells have binding sites for rat atrial natriuretic factor (ANF), as demonstrated autoradiographically by using the ~2SI-labelled peptide. Patch-clamp recording revealed that ANF reduces acetylcholine (ACh)-induced membrane currents in chromaffin cells at physiological membrane potentials. The effect was dose-dependent with the ICs0 value being 5.2 pM ANF and the Hill coefficient close to 1. The channel block was absent at positive membrane potentials, indicating a non-competitive interaction of ANF with the open ACh receptor channel. Fragments of ANF had a much less pronounced action, which is possibly due to their structure and molecular charge being different to ANF. The block of nicotinic ACh receptor channels may enable ANF to control the secretion of catecholamines from adrenal chromaffin cells.

Natriuretic Peptides Inhibit Nicotine‐Induced Whole‐Cell Currents and Catecholamine Secretion in Bovine Chromaffin Cells: Evidence for the Involvement of the Atrial Natriuretic Factor R2 Receptors

“…This supports the interpretation of the involvement of the ANF-R, receptors and challenges the possibility of nonspecific ionic interactions with the nicotinic receptor ionophore complex. Indeed, as shown by Bormann et al . (1989), non-receptor-dependent inhibition of nicotinic currents by NPs occurs only at high peptide concentrations ( > 1 PM) .…”

“…This selective expression of the ANF-R,,, subtype is consistent with previously published distribution of this receptor in other species (Wilcox et al ., 1991 ;Féthière et al ., 1993) and with the major localization of CNP within the nervous system (Ueda et A ., 1991 ;Minamino et al ., 1993) . The micromolar IC 5 values for ANF inhibition of nicotinic currents previously reported by Bormann et al ( 1989) do not reflect normal physiological conditions . We therefore conducted patch-clamp studies to verify if CNP displayed current inhibition properties at nanomolar concentrations, in agreement with ANF-R,,, receptor affinities.…”

“…Bovine chromaffin cells display ANF binding sites, but their exact nature has not yet been fully characterized (Heisler and Morrier, 1988 ;Bormann et al ., 1989) .…”

“…Electrophysiological studies on isolated chromaffin cells have also shown that ANF is able to inhibit nicotine-induced inward currents, a mechanism that could perhaps explain the inhibition of catecholamine secretion observed in PC 12 cells . However, the high IC, (5 .2 N,M) of the response to ANF does not correlate with the low nanomolar affinities of the ANF receptor (Bormann et al ., 1989) . In the present study, we provide additional evidence that bovine chromaffin cells actually express the CNP-and not the ANF-specific receptor subtype .…”

Cyclic GMP Regulates Nicotine‐Induced Secretion from Cultured Bovine Adrenal Chromaffin Cells: Effects of 8–Bromo–Cyclic GMP, Atrial Natriuretic Peptide, and Nitroprusside (Nitric Oxide)

“…ANP inhibits secretion from PC12 cells (Drewett el al., 1988); however, these cells differ in many respects from bovine chromaffin cells. Bormann et al (1989) found that ANP inhibited acetylcholine-induced currents in bovine chromaffin cells. This inhibitory effect of ANP was only seen at concentrations of ANP greater than those used here (> 1 p M ) .…”