Neuronal nicotinic @entity934 receptors of chromaffin cells in the adrenal medulla are physiologically activated by @entity934 to mediate @entity2922 release into the bloodstream. The present study examined the subunit composition and functional properties of @entity35 chromaffin cell neuronal nicotinic @entity934 receptors using molecular biology, immunocytochemistry and whole-cell patch-clamp. Reverse transcription-polymerase chain reaction analysis indicated the presence of alpha2, alpha3, alpha4, alpha5, alpha7, beta2 and beta4 transcripts (alpha6 and beta3 could not be detected). Immunocytochemistry revealed most cells positive for alpha3, beta2, beta4 and alpha5 proteins. Few cells were immunoreactive for alpha2 and alpha4, while none was for alpha7. At single-cell level, colocalization could be demonstrated for alpha3alpha5 and alpha4beta2. Western blot analysis confirmed antibody specificity for alpha3, alpha4, alpha5, beta2 and beta4 subunits. Inward currents elicited by @entity1239 pulses were insensitive to alpha-bungarotoxin and low doses of @entity2512 , demonstrating lack of functional alpha7 receptors. Partial block of @entity1239 currents was observed with either AuIB alpha-conotoxin (selective against alpha3beta4 receptors) or MII alpha-conotoxin (selective against alpha3beta2 receptors). With high concentrations of co-applied toxins, antagonism occlusion developed, suggesting loss of subunit selectivity. Antagonism by @entity6325 summated nonlinearly with AuIB and MII inhibition, confirming heterogeneity of neuronal nicotinic @entity934 receptor block. The present results suggest that the most frequently encountered receptors of @entity35 chromaffin cells should comprise alpha3beta4, alpha3beta2 with the addition of alpha5 subunits. Because of the prevailing subunit composition, @entity35 chromaffin cell neuronal nicotinic @entity934 receptors are suitable models, particularly for the alpha3beta4 subclasses of @entity1 brain receptors recently demonstrated in discrete cerebral areas.

Molecular biology and electrophysiology of neuronal nicotinic receptors of XXXX chromaffin cells.

@entity1 :: ('9606', 'Species') :: ['mammalian'] @entity2512 :: ('MESH:C054634', 'Chemical') :: ['methyllycaconitine'] @entity1239 :: ('MESH:D009538', 'Chemical') :: ['nicotine'] @entity6325 :: ('MESH:D004079', 'Chemical') :: ['dihydro-beta-erythroidine'] @entity2922 :: ('CHEBI:33567', 'Chemical') :: ['catecholamine'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity934 :: ('MESH:D000109', 'Chemical') :: ['acetylcholine']
@entity35 :: (10116,Species) :: ['rat']
