Abstract

Cephalopods have a highly developed CNS and exhibit a number of complex behaviors, show a marked ability to learn, and provide good model preparations for the investigation of neurobiology. Their CNS exhibits a functional differentiation into distinct lobes and has been the subject of extensive anatomical, histological, behavioral and neurophysiological investigations [1,2]. Their CNS contain a variety of putative neurotransmitters [3]. Particularly intriguing is the presence in several lobes of the molecules involved in the signalling Glu/NMDA-NO-cGMP [4,5].Poly(ADPribosyl)ation is implicated in glutamate neurotoxicity that involves N-methyl-D-aspartate receptors (NMDA-R) and is mediated by activation of neuronal nitric oxide synthase (nNOS) [6].Our study was aimed to investigate the poly(ADPR) metabolism in the CNS of O. vulgaris. The presence of PARP was initially evidenced by the classic enzymatic assay in homogenates from optic lobes and brain. Specific activities were comparable for both tissues, although a slightly higher value was measured in the optic lobes. Immunoblotting of SDS-PAGE separated proteins with commercial anti-PARP catalytic domain antibodies confirmed the results of enzyme activity, giving a net signal at [email protected] kDa.Furthermore, a specific PARP localization was determined on tissue slices by immunohistochemistry with the same antibodies. Immunoreactivity was revealed in the optic nerves as well as in the plexiform layer of optic lobe and in the neuropils of the vertical complex. The co-presence in O. vulgaris of active poly(ADPribose)/NO metabolisms and of the signaling pathway mediated by Glu/NMDA makes this CNS a biological model to study the relationship between the three systems and neuronal injury.References: 1.Boycott BB: Proc R Soc Lond B, 1961; 153: 503-534 2.Young JZ: The anatomy of the nervous system of O. vulgaris. Oxford, Clarendon, 1971 3.Messenger JB: Invert Neurosci, 1996; 2: 95-114 4.Di Cosmo A et al: J Comp Neurol, 2000; 428: 411-27 5.Di Cosmo A, Di Cristo C: Proceeding of CECN, Krakow 2001, Poland 6.Zhang J et al: Science, 1994; 263: 687-689

Keywords: PARP, cephalopods, NMDA, NOS, octopus