Involvement of the cAMP-dependent pathway in the reduction of epileptiform bursting caused by somatostatin in the mouse hippocampus.
The cyclic AMP pathway is major signal transduction system involved in hippocampal neurotransmission. Recently, the peptide somatostatin-14 (SRIF) has emerged as a key signal that, by activating its receptors, inhibits epileptiform bursting in the mouse hippocampus. Little is known on transduction mechanisms, which may mediate SRIF function in native cell/tissues. Using a well-established model of epileptiform activity induced by Mg(2+)-free medium with 4-aminopyridine [0 Mg(2+)/4-aminopyridine (4-AP)] in mouse hippocampal slices, we demonstrated that protein kinase A (PKA)-related signaling is upregulated by hippocampal bursting and that treatment with SRIF normalizes this upregulation. We also demonstrated that the SRIF-induced inhibition of PKA impairs phosphorylation of the NMDA receptor subunit NR1. Extracellular recordings of the 0 Mg(2+)/4-AP-induced hippocampal discharge from the CA3 region demonstrated that treating slices with compounds, which interfere with PKA activity, prevent SRIF inhibition of epileptiform bursting. Our results suggest that SRIF modulation of hippocampal activity may involve PKA-related signaling.
Ristori
Chiara
C
Cardiac and Thoracic Department, University of Pisa, via Paradisa 2, 56124, Pisa, Italy.
Cammalleri
Maurizio
M
Martini
Davide
D
Pavan
Barbara
B
Liu
Yanqiang
Y
Casini
Giovanni
G
Dal Monte
Massimo
M
Bagnoli
Paola
P
D015761:4-Aminopyridine; D000818:Animals; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013004:Somatostatin / Q000494:pharmacology / Q000502:physiology*
D012333:RNA, Messenger; D013004:Somatostatin; D015761:4-Aminopyridine; D017868:Cyclic AMP-Dependent Protein Kinases