title: A role for picomolar concentrations of pregnenolone sulfate in synaptic activity-dependent Ca2+ signaling and CREB activation.
abstract: Fast excitatory synaptic transmission that is contingent upon N-methyl d-aspartate receptor (NMDAR) function contributes to core information flow in the central nervous system and to the plasticity of neural circuits that underlie cognition. Hypoactivity of excitatory NMDAR-mediated neurotransmission is hypothesized to underlie the pathophysiology of schizophrenia, including the associated cognitive deficits. The neurosteroid pregnenolone (PREG) and its metabolites pregnenolone sulfate (PregS) and allopregnanolone in serum are inversely associated with cognitive improvements after oral PREG therapy, raising the possibility that brain neurosteroid levels may be modulated therapeutically. PregS is derived from PREG, the precursor of all neurosteroids, via a single sulfation step and is present at low nanomolar concentrations in the central nervous system. PregS, but not PREG, augments long-term potentiation and cognitive performance in animal models of learning and memory. In this report, we communicate the first observation that PregS, but not PREG, is a potent (EC50 ∼2 pM) enhancer of intracellular Ca(2+) that is contingent upon neuronal activity, NMDAR-mediated synaptic activity, and L-type Ca(2+) channel activity. Low picomolar PregS similarly activates cAMP response element-binding protein (CREB) phosphorylation (within 10 minutes), an essential memory molecule, via an extracellular-signal-regulated kinase/mitogen-activated protein kinase signal transduction pathway. Taken together, the results are consistent with a novel biologic role for the neurosteroid PregS that acts at picomolar concentrations to intensify the intracellular response to glutamatergic signaling at synaptic but not extrasynaptic, NMDARs by differentially augmenting CREB activation. This provides a genomic signal transduction mechanism by which PregS could participate in memory consolidation of relevance to cognitive function.
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts.
authors: Conor C
authors: CC
authors: Smith
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts.
authors: Stella C
authors: SC
authors: Martin
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts.
authors: Kavitha
authors: K
authors: Sugunan
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts.
authors: Shelley J
authors: SJ
authors: Russek
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts.
authors: Terrell T
authors: TT
authors: Gibbs
authors: Laboratory of Molecular Neurobiology (C.C.S., S.C.M., K.S., T.T.G., D.H.F.), Department of Pharmacology & Experimental Therapeutics, Laboratory of Translational Epilepsy (S.J.R.), Boston University School of Medicine, Boston, Massachusetts dfarb@bu.edu.
authors: David H
authors: DH
authors: Farb
mesh_terms: D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism; D020013:Calcium Signaling; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D020128:Inhibitory Concentration 50; D020935:MAP Kinase Signaling System; D008297:Male; D011284:Pregnenolone / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D055366:Synaptic Potentials
chemical_list: D020746:Calcium Channels, L-Type; D017362:Cyclic AMP Response Element-Binding Protein; C018370:pregnenolone sulfate; D011284:Pregnenolone