RT Journal Article SR Electronic T1 Nitric oxide and peptide neurohormones activate cGMP synthesis in the crab stomatogastric nervous system JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 1614 OP 1622 DO 10.1523/JNEUROSCI.16-05-01614.1996 VO 16 IS 5 A1 NL Scholz A1 MF Goy A1 JW Truman A1 K Graubard YR 1996 UL http://www.jneurosci.org/content/16/5/1614.abstract AB In the neural circuits that comprise the crustacean stomatogastric nervous system (STNS), synaptically delivered neurotransmitters and circulating neurohormones elicit a wide range of rhythmic motor outputs. However, functional roles for second messengers in this system are poorly understood. Here we demonstrate two different signaling pathways that control the synthesis of 3′,5′-cGMP in the crab STNS. One pathway is activated by nitric oxide (NO) and is mediated by a cytoplasmic guanylate cyclase. A second pathway is stimulated by peptide-containing extracts from a crab neurohemal organ that activate a membrane-associated guanylate cyclase. Using whole-mount immunocytochemistry to localize individual cGMP-containing cells, we find that NO elevates intracellular cGMP in a small subset of STNS neurons. Immunopositive cells are found predominantly in the stomatogastric ganglion, with a few additional cells located in the oesophageal and commissural ganglia. Crab tissues differ in their sensitivities to NO and to the peptide-containing extract. The NO- mediated pathway is apparently restricted to the nervous system, whereas the peptidemediated pathway is present in every tissue tested. The results of these experiments demonstrate that multiple signaling pathways involving cGMP are present in the STNS and suggest that this second messenger may help control the metabolic and physiological status of these motor circuits.