Abstract

GARAY, José L et al. cAMP/PKA - dependent regulation of the high affinity choline transporter is not mediated by dopamine in retinal neurons. AVFT [online]. 2010, vol.29, n.4, pp.66-71. ISSN 0798-0264.

The high affinity choline transporter (HAChT) activity is considered to be the rate-limiting step in acetylcholine (ACh) synthesis in the cholinergic terminal. Recent studies show that HAChT contains consensus serine and threonine residues for protein kinase A (PKA) phosphorylation. Using chick retinal neurons evaluated the effects of the second messenger cAMP on the HAChT activity. The increase of the intracellular cAMP levels through phosphodiesterase inhibition, adenilatecyclase activation or using a phosphodiesterase-resistant cAMP analog decreased HAChT activity between 29 and 69%. Moreover, the activation of dopamine D₁-type receptors increase the intracellular cAMP levels and activates PKA, however, the treatment with dopamine D₁ or D₂ receptor antagonists does not induce changes on transporter activity.

Keywords : High affinity choline transporter; protein kinase A; dopamine.