Involvement of the cAMP-dependent pathway in the reduction of epileptiform bursting caused by somatostatin in the mouse hippocampus

Ristori, Chiara; Cammalleri, Maurizio; Martini, Davide; Pavan, Barbara; Liu, Yanqiang; Casini, G.; Monte, Massimo Dal; Bagnoli, Paola

doi:10.1007/s00210-008-0338-z

Cited by 13 publications

(16 citation statements)

References 73 publications

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“…Third, inhibition of PKA by KT 5720 and Rp-cAMPS significantly reduced but not completely blocked CRF-induced increases in epileptiform activity. In accordance with our results, tremendous evidence demonstrates that AC/cAMP/PKA pathway plays a facilitatory role in epilepsy [53], [54], [55], [56], [57], [58].…”

Section: Discussionsupporting

confidence: 93%

“…Because CRF 2 receptors are coupled to AC/cAMP/PKA pathway and there is strong evidence demonstrating that cAMP and PKA signals exert a tonic control of epilepsy [53], [54], [55], [56], [57], [58], we tested the roles of this pathway in CRF-mediated facilitation of epileptiform activity. Slices were pretreated with the selective AC inhibitor MDL 12330A (50 µM) for ∼20 min and the same concentration of MDL 12330A was included in the PTX-containing extracellular solution and applied in the bath before and during the application of CRF.…”

Section: Resultsmentioning

confidence: 99%

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Corticotropin-Releasing Factor Facilitates Epileptiform Activity in the Entorhinal Cortex: Roles of CRF2 Receptors and PKA Pathway

2014

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Whereas corticotropin-releasing factor (CRF) has been considered as the most potent epileptogenic neuropeptide in the brain, its action site and underlying mechanisms in epilepsy have not been determined. Here, we found that the entorhinal cortex (EC) expresses high level of CRF and CRF2 receptors without expression of CRF1 receptors. Bath application of CRF concentration-dependently increased the frequency of picrotoxin (PTX)-induced epileptiform activity recorded from layer III of the EC in entorhinal slices although CRF alone did not elicit epileptiform activity. CRF facilitated the induction of epileptiform activity in the presence of subthreshold concentration of PTX which normally would not elicit epileptiform activity. Bath application of the inhibitor for CRF-binding proteins, CRF6-33, also increased the frequency of PTX-induced epileptiform activity suggesting that endogenously released CRF is involved in epileptogenesis. CRF-induced facilitation of epileptiform activity was mediated via CRF2 receptors because pharmacological antagonism and knockout of CRF2 receptors blocked the facilitatory effects of CRF on epileptiform activity. Application of the adenylyl cyclase (AC) inhibitors blocked CRF-induced facilitation of epileptiform activity and elevation of intracellular cyclic AMP (cAMP) level by application of the AC activators or phosphodiesterase inhibitor increased the frequency of PTX-induced epileptiform activity, demonstrating that CRF-induced increases in epileptiform activity are mediated by an increase in intracellular cAMP. However, application of selective protein kinase A (PKA) inhibitors reduced, not completely blocked CRF-induced enhancement of epileptiform activity suggesting that PKA is only partially required. Our results provide a novel cellular and molecular mechanism whereby CRF modulates epilepsy.

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Section: Discussionsupporting

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Corticotropin-Releasing Factor Facilitates Epileptiform Activity in the Entorhinal Cortex: Roles of CRF2 Receptors and PKA Pathway

2014

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“…Hippocampal slices were prepared as previously described (Cammalleri et al. 2004, 2006; Ristori et al. 2008a,b).…”

Section: Methodsmentioning

confidence: 99%

“…Whether pre‐ and/or post‐synaptic mechanisms mediate the SRIF‐induced inhibition of hippocampal activity still remains to be clarified. In an in vitro model of hippocampal hyperactivity, we have recently demonstrated that SRIF decreases the phosphorylation of a protein kinase A‐dependent site on NMDA receptor subunit NR1 (Ristori et al. 2008a).…”

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confidence: 99%

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Functional effects of somatostatin receptor 1 activation on synaptic transmission in the mouse hippocampus

Cammalleri

Martini

Timperio

et al. 2009

Journal of Neurochemistry

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Somatostatin-14 (SRIF) co-localizes with GABA in the hippocampus and regulates neuronal excitability. A role of SRIF in the control of hippocampal activity has been proposed, although the exact contribution of each SRIF receptor (sst 1 -sst 5 ) in mediating SRIF action requires some clarification. We used hippocampal slices of wild-type and sst 1 knockout (KO) mice and selective pharmacological tools to provide conclusive evidence for a role of sst 1 in mediating SRIF inhibition of synaptic transmission. With single-and double-label immunohistochemistry, we determined the distribution of sst 1 in hippocampal slices and we quantified sst 1 colocalization with SRIF. With electrophysiology, we found that sst 1 activation with CH-275 inhibited both the NMDA-and the a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-mediated responses. Results from sst 1 KO slices confirmed the specificity of CH-275 effects; sst 1 activation did not affect the inhibitory transmission which was in contrast increased by sst 4 activation with L-803,087 in both wild-type and sst 1 KO slices. The AMPA-mediated responses were increased by L-803,087. Functional interaction between sst 1 and sst 4 is suggested by the finding that their combined activation prevented the CH-275-induced inhibition of AMPA transmission. The involvement of pre-synaptic mechanisms in mediating inhibitory effects of sst 1 on excitatory transmission was demonstrated by the finding that CH-275 (i) increased the paired-pulse facilitation ratio, (ii) did not influence the AMPA depolarization in the presence of tetrodotoxin, and (iii) inhibited glutamate release induced by epileptiform treatment. We conclude that SRIF control of excitatory transmission through an action at sst 1 may represent an important contribution to the regulation of hippocampal activity.

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Linalool from Rosewood (Aniba rosaeodora Ducke) Oil Inhibits Adenylate Cyclase in the Retina, Contributing to Understanding its Biological Activity

Sampaio

Maia

Parijós

et al. 2011

Phytotherapy Research

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Rosewood oil (RO) (Aniba rosaeodora Ducke) is rich in linalool, a monoterpene alcohol, which has well studied anxiolytic, sedative and anticonvulsant effects. The inhibition of the increases in cAMP protects against seizures in a diversity of models of epilepsy. In this paper, the principal aim was to investigate the effects of RO, (±)-linalool and (-)-linalool) on adenylate cyclase. They were tested in chick retinas and forskolin was used to stimulate the enzyme target. The phosphodiesterase inhibitor, 4-(3-butoxy-4-methoxybenzyl)-imidazolidin-2-one, and the non-selective adenosine receptor antagonist 3-isobutyl-methyl-xanthine (IBMX), were used to control the participation of phosphodiesterase and adenosine receptors in the resulting effects, respectively. The cAMP accumulation was measured by enzyme immune assay (EIA). Rosewood oil, (-)-linalool and (±)-linalool inhibited exclusively the cAMP accumulation stimulated by forskolin, even when adenosine receptors were blocked with IBMX. The IC(50) values (in μ m concentration range) calculated from their concentration response-curves were not statistically different, however, the compounds presented a different relative efficacy. These results extend the range of subcellular mechanisms underlying the relaxant action of linalool on the central nervous system.

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Involvement of the cAMP-dependent pathway in the reduction of epileptiform bursting caused by somatostatin in the mouse hippocampus

Cited by 13 publications

References 73 publications

Corticotropin-Releasing Factor Facilitates Epileptiform Activity in the Entorhinal Cortex: Roles of CRF2 Receptors and PKA Pathway

Corticotropin-Releasing Factor Facilitates Epileptiform Activity in the Entorhinal Cortex: Roles of CRF2 Receptors and PKA Pathway

Functional effects of somatostatin receptor 1 activation on synaptic transmission in the mouse hippocampus

Linalool from Rosewood (Aniba rosaeodora Ducke) Oil Inhibits Adenylate Cyclase in the Retina, Contributing to Understanding its Biological Activity

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