PT  - JOURNAL ARTICLE
AU  - Peter V. Lovell
AU  - David P. McCobb
TI  - Pituitary Control of BK Potassium Channel Function and Intrinsic Firing Properties of Adrenal Chromaffin Cells
AID  - 10.1523/JNEUROSCI.21-10-03429.2001
DP  - 2001 May 15
TA  - The Journal of Neuroscience
PG  - 3429--3442
VI  - 21
IP  - 10
4099  - http://www.jneurosci.org/content/21/10/3429.short
4100  - http://www.jneurosci.org/content/21/10/3429.full
SO  - J. Neurosci.2001 May 15; 21
AB  - The discovery that the hypothalamic–pituitary–adrenocortical (HPA) endocrine stress axis controls an alternative splicing decision in chromaffin Slo-encoded BK (big potassium) channels raised the possibility that activation of the HPA could serve as a mechanism to tune the intrinsic electrical properties of epinephrine-secreting adrenal chromaffin cells. To test this, we compared BK functional properties and cell excitability in chromaffin cells from normal and hypophysectomized (pituitary-ablated) rats. Hypophysectomy was found to alter the voltage dependence and kinetics of BK gating, making channels less accessible for activation from rest. Perforated-patch recordings revealed changes in action potential waveform and repetitive firing properties. The maximum number of spikes that could be elicited with a 2 sec depolarizing current pulse was reduced by ∼50% by hypophysectomy. The results indicate that pituitary hormones can adapt the mechanics of adrenal catecholamine release by tailoring BK channel function.