NK-3 receptor activation depolarizes and induces an after-depolarization in pyramidal neurons in gerbil cingulate cortex.
The involvement of tachykinins in cortical function is poorly understood. To study the actions of neurokinin-3 (NK3) receptor activation in frontal cortex, whole cell patch clamp recordings were performed from pyramidal neurons in slices of cingulate cortex from juvenile gerbils. Senktide (500nM), a selective NK3 receptor agonist, induced a transient increase in spontaneous EPSPs in layer V pyramidal neurons, accompanied by a small depolarization ( approximately 4 mV). EPSPs during senktide had a larger amplitude and faster 10-90% rise time than during control. Senktide induced a transient depolarization in layer II/III pyramidal neurons, which often reached threshold for spikes. The depolarization ( approximately 6 mV) persisted in TTX, and was accompanied by an increase in input resistance. Senktide also transiently induced a slow after-depolarization, which appeared following a depolarizing pulse. The slow after-depolarization persisted in TTX. These data suggest that activation of NK3 receptors on layer II/III pyramidal neurons induce post-synaptic depolarization and an after-depolarization, which could be mediated by blockade of a leak potassium conductance and a non-selective cation conductance, respectively.
Rekling
Jens C
JC
H. Lundbeck A/S, Biological Research, Ottiliavej 9, DK-2500 Valby, Denmark. jre@lundbeck.com
D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005849:Gerbillinae; D006179:Gyrus Cinguli / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism*; D018042:Receptors, Neurokinin-3 / Q000819:agonists / Q000378:metabolism*; D013373:Substance P / Q000031:analogs & derivatives* / Q000494:pharmacology
D010446:Peptide Fragments; D018042:Receptors, Neurokinin-3; C054724:senktide; D013373:Substance P