A role for cyclic nucleotide monophosphates in synaptic modulation by a crayfish neuropeptide

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• 作者：Amit Badhwar ; Andrea D. Weston ; Jillian B. Murray and A. Joffre Mercier
• 关键词：FMRFamide ; Neuropeptide ; Crustacean ; Protein kinase A ; Protein kinase G
• 刊名：Peptides
• 出版年：2006
• 出版时间：June 2006
• 年：2006
• 卷：27
• 期：6
• 页码：1281-1290
• 全文大小：583 K

文摘

DF₂ (DRNFLRFamide), a FMRFamide-like peptide, has been shown to increase the amount of transmitter released at crayfish neuromuscular junctions. Here, we examined a possible role for the cyclic nucleotide monophosphates, cAMP and cGMP, in DF₂'s effects on synaptic transmission. The effects of DF₂ on synaptic transmission were monitored by recording excitatory postsynaptic potentials (EPSPs) in the deep abdominal extensor muscles of the crayfish, Procambarus clarkii. A number of activators and inhibitors were used to determine whether or not cAMP, cGMP, protein kinase A (PKA) and protein kinase G (PKG) mediate the effect of this neuropeptide. Phosphodiesterase inhibitors, known to inhibit the breakdown of cAMP (IBMX) and/or cGMP (mdBAMQ), potentiate the effect of DF₂ on synaptic transmission. Activators of PKA (Sp-cAMPS) and PKG (8-pCPT-cGMP) increase EPSP amplitude, mimicking the effects of DF₂. Inhibitors of PKA (Rp-cAMPS) and PKG (Rp-8-pCPT-cGMPS) each block a portion of the response to the peptide, and when applied together these two inhibitors completely block the response. Taken together, these results indicate that cyclic nucleotides and cyclic nucleotide-dependent protein kinases are necessary components of the pathway underlying modulation by this neuropeptide.