TGFbeta2 mediates rapid inhibition of calcium influx in identified cholinergic basal forebrain neurons

• Transforming growth factors betas (TGFbetas) are known to have important roles in neuronal survival and can be upregulated in disease. However, unlike many other trophic factors, nothing is known about the rapid neurotransmitter-like actions of TGFbeta in the CNS. We explored this by examining the effects of TGFbeta on calcium influx of large enzymatically dissociated basal forebrain neurons. We show that brief application of TGFbeta2, but not TGFbeta1, to fura-2AM-loaded neurons reversibly and acutely (within seconds) inhibited K(+)-evoked calcium influx. Moreover, using single-cell RT-PCR, we confirmed that the large TGFbeta2-responsive neurons presented a cholinergic phenotype. Investigation of the signaling mechanism underlying TGFbeta2 actions using whole-cell recordings of calcium currents revealed that TGFbeta2-mediated responses were insensitive to the nonhydrolyzable GTP analogue GTPgammaS. However, TGFbeta2-mediated calcium current reductions were prevented by intracellular perfusion of a Smad2/3 peptide antagonist. Together, these results suggest that TGFbeta2 can acutely regulate the excitability of basal forebrain cholinergic neurons through an atypical signaling mechanism.

Nyckelord

Animals

Base Sequence

Calcium Signaling/*drug effects

Choline O-Acetyltransferase/genetics

Cholinergic Fibers/drug effects/metabolism

DNA; Complementary/genetics

Glutamate Decarboxylase/genetics

Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology

Isoenzymes/genetics

Neurons/*drug effects/*metabolism

Prosencephalon/drug effects/metabolism

Rats

Rats; Sprague-Dawley

Second Messenger Systems

Transforming Growth Factor beta/*pharmacology

Publikations- och innehållstyp

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