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Social Stress Alters Expression of Large Conductance Calcium‐Activated Potassium Channel Subunits in Mouse Adrenal Medulla and Pituitary Glands
Author(s) -
Chatterjee O.,
Taylor L. A.,
Ahmed S.,
Nagaraj S.,
Hall J. J.,
Finckbeiner S. M.,
Chan P. S.,
Suda N.,
King J. T.,
Zeeman M. L.,
McCobb D. P.
Publication year - 2009
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.2009.01823.x
Subject(s) - endocrinology , medicine , corticosterone , biology , anterior pituitary , gene expression , alternative splicing , adrenal medulla , adrenal gland , messenger rna , hormone , gene , genetics , catecholamine
Large conductance calcium‐activated potassium (BK) channels are very prominently expressed in adrenal chromaffin and many anterior pituitary cells, where they shape intrinsic excitability complexly. Stress‐ and sex‐steroids regulate alternative splicing of Slo‐α, the pore‐forming subunit of BK channels, and chronic behavioural stress has been shown to alter Slo splicing in tree shrew adrenals. In the present study, we focus on mice, measuring the effects of chronic behavioural stress on total mRNA expression of the Slo‐α gene, two key BK channel β subunit genes (β2 and β4), and the ‘STREX’ splice variant of Slo‐α. As a chronic stressor, males of the relatively aggressive SJL strain were housed with a different unfamiliar SJL male every 24 h for 19 days. This ‘social‐instability’ paradigm stressed all individuals, as demonstrated by reduced weight gain and elevated corticosterone levels. Five quantitative reverse transcriptase‐polymerase chain assays were performed in parallel, including β‐actin, each calibrated against a dilution series of its corresponding cDNA template. Stress‐related changes in BK expression were larger in mice tested at 6 weeks than 9 weeks. In younger animals, Slo‐α mRNA levels were elevated 44% and 116% in the adrenal medulla and pituitary, respectively, compared to individually‐housed controls. β2 and β4 mRNAs were elevated 162% and 194% in the pituitary, but slightly reduced in the adrenals of stressed animals. In the pituitary, dominance scores of stressed animals correlated negatively with α and β subunit expression, with more subordinate individuals exhibiting levels that were three‐ to four‐fold higher than controls or dominant individuals. STREX variant representation was lower in the subordinate subset. Thus, the combination of subunits responding to stress differs markedly between adrenal and pituitary glands. These data suggest that early stress will differentially affect neuroendocrine cell excitability, and call for detailed analysis of functional consequences.