PT  - JOURNAL ARTICLE
AU  - John M. Power
AU  - Christina Bocklisch
AU  - Peter Curby
AU  - Pankaj Sah
TI  - Location and Function of the Slow Afterhyperpolarization Channels in the Basolateral Amygdala
AID  - 10.1523/JNEUROSCI.1045-10.2011
DP  - 2011 Jan 12
TA  - The Journal of Neuroscience
PG  - 526--537
VI  - 31
IP  - 2
4099  - http://www.jneurosci.org/content/31/2/526.short
4100  - http://www.jneurosci.org/content/31/2/526.full
SO  - J. Neurosci.2011 Jan 12; 31
AB  - The basolateral amygdala (BLA) assigns emotional significance to sensory stimuli. This association results in a change in the output (action potentials) of BLA projection neurons in response to the stimulus. Neuronal output is controlled by the intrinsic excitability of the neuron. A major determinant of intrinsic excitability in these neurons is the slow afterhyperpolarization (sAHP) that follows action potential (AP) trains and produces spike-frequency adaptation. The sAHP is mediated by a slow calcium-activated potassium current (sIAHP), but little is known about the channels that underlie this current. Here, using whole-cell patch-clamp recordings and high-speed calcium imaging from rat BLA projection neurons, we examined the location and function of these channels. We determined the location of the sIAHP by applying a hyperpolarizing voltage step during the sIAHP and measuring the time needed for the current to adapt to the new command potential, a function of its electrotonic distance from the somatic recording electrode. Channel location was also probed by focally uncaging calcium using a UV laser. Both methodologies indicated that, in BLA neurons, the sIAHP is primarily located in the dendritic tree. EPSPs recorded at the soma were smaller, decayed faster, and showed less summation during the sAHP. Adrenergic stimulation and buffering calcium reduced the sAHP and the attenuation of the EPSP during the sAHP. The sAHP also modulated the AP in the dendrite, reducing the calcium response evoked by a single AP. Thus, in addition to mediating spike-frequency adaptation, the sIAHP modulates communication between the soma and the dendrite.