Independent roles of calcium and voltage-dependent potassium currents in controlling spike frequency adaptation in lateral amygdala pyramidal neurons.
The calcium-dependent afterhyperpolarization (AHP) that follows trains of action potentials is responsible for controlling action potential firing patterns in many neuronal cell types. We have previously shown that the slow AHP contributes to spike frequency adaptation in pyramidal neurons in the rat lateral amygdala. In addition, a dendritic voltage-gated potassium current mediated by Kv1.2-containing channels also suppresses action potential firing in these neurons. In this paper we show that this voltage-gated potassium current and the slow AHP act together to control spike frequency adaptation in lateral amygdala pyramidal neurons. The two currents have similar effects on action potential number when firing is evoked either by depolarizing current injections or by synaptic stimulation. However, they differ in their control of firing frequency, with the voltage-gated potassium current but not the slow AHP determining the initial frequency of action potential firing. This dual mechanism of controlling firing patterns is unique to lateral amygdala neurons and is likely to contribute to the very low levels of firing seen in lateral amygdala neurons in vivo.
Faber
E S Louise
ES
Queensland Brain Institute, University of Queensland, Brisbane, QLD 4072, Australia.
Sah
Pankaj
P
D015761:4-Aminopyridine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000222:Adaptation, Physiological / Q000502:physiology*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000679:Amygdala / Q000166:cytology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium; D002217:Carbachol / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004347:Drug Interactions; D004546:Elapid Venoms / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D018408:Patch-Clamp Techniques / Q000379:methods; D010721:Phosphinic Acids / Q000494:pharmacology; D010852:Picrotoxin / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
D015761:4-Aminopyridine; D000318:Adrenergic beta-Agonists; D001285:Atropine; D002118:Calcium; D002217:Carbachol; D018679:Cholinergic Agonists; D004546:Elapid Venoms; D018756:GABA Antagonists; D007545:Isoproterenol; D008734:Methoxyhydroxyphenylglycol; D018727:Muscarinic Antagonists; D009638:Norepinephrine; D010721:Phosphinic Acids; D010852:Picrotoxin; D026902:Potassium Channel Blockers; D011412:Propanolamines; C085075:CGP 55845A; C020273:dendrotoxin; C010117:3,4-dihydroxyphenylglycol