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The cAMP-dependent kinase pathway does not sensitize the cloned vanilloid receptor type 1 expressed in xenopus oocytes or Aplysia neurons.
Lee, Y S; Lee, J A; Jung, J; Oh, U; Kaang, B K.
Affiliation
  • Lee YS; Molecular Neurobiology Laboratory, Institute of Molecular Biology and Genetics, School of Biological Sciences, College of Natural Sciences, Seoul National University, South Korea.
Neurosci Lett ; 288(1): 57-60, 2000 Jul 07.
Article in En | MEDLINE | ID: mdl-10869815
ABSTRACT
Capsaicin-activated channels present in sensory neurons are ligand-gated cation channels that largely account for mediating some types of pain. The cAMP-dependent protein kinase (PKA) signal pathway was suggested to mediate the prostaglandin-induced enhancement of capsaicin-evoked inward current (I(CAP)) in rat sensory neurons. It is not clear, however, whether PKA acts directly on the capsaicin-sensitive channel that is responsible for I(CAP). To address this issue, we overexpressed the cloned capsaicin receptor, VR1, in heterologous expression systems such as Xenopus oocytes or Aplysia R2 neuron and stimulated PKA pathways. As a result, activation of PKA by applying either 8-bromo-cAMP or forskolin with 3-isobutyl-1-methylxanthine or through activation of beta(2) adrenergic receptors failed to enhance I(CAP) in oocytes or R2 neurons expressing VR1. Our results raise two possibilities. (1) Direct phosphorylation of VR1 by PKA may not be responsible for the sensitization; instead, phosphorylation of regulatory proteins associated with VR1 would account for the sensitization of I(CAP) evoked by prostaglandin E(2) in dorsal root ganglion (DRG) neurons. (2) DRG neurons may have a different PKA signaling mechanism that is not replicable in Xenopus oocytes or Aplysia R2 neurons.
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Collection: 01-internacional Database: MEDLINE Main subject: Receptors, Drug / Signal Transduction / Cyclic AMP-Dependent Protein Kinases / Neurons Limits: Animals Language: En Journal: Neurosci Lett Year: 2000 Document type: Article
Search on Google
Collection: 01-internacional Database: MEDLINE Main subject: Receptors, Drug / Signal Transduction / Cyclic AMP-Dependent Protein Kinases / Neurons Limits: Animals Language: En Journal: Neurosci Lett Year: 2000 Document type: Article