title: Primary structure, behavioral and electroencephalographic effects of an epileptogenic peptide from the sea anemone Bunodosoma cangicum.
abstract: The primary structure of cangitoxin (CGX), a 4958 Da peptide from the sea anemone Bunodosoma cangicum, was determined: GVACRCDSDGPTVRGNSLSGTLWLTGGCPSGWHNCRGSGPFIGYCCKK. CGX contains all the 11 residues that are conserved and the 5 that are conservatively substituted within or between the type 1 and type 2 sequences of sea anemone peptides with specific action on voltage-sensitive sodium channels. Furthermore, it also has 6 identities (Asp9, Arg14, Asn16, Leu18, Trp33 and Lys48) and 1 homology (Arg36) in the 8 residues of the pharmacophore of the sea anemone ApB which are essential for interaction with mammalian sodium channels. The intrahippocampal injection of CGX induces several sequential behavioral alterations--episodes of akinesia alternating with facial automatisms and head tremor, salivation, rearing, jumping, barrel-rolling, wet dog shakes and forelimb clonic movements--and the electroencephalography analysis shows that they were followed by important seizure periods that gradually evolved to status epilepticus that lasted 8-12 h, similar to that observed in the acute phase of the pilocarpine model of epilepsy. These results suggest that CGX may be an important tool to develop a new experimental model of status epilepticus which may contribute to understanding the etiology of epilepsy and to test the effects of new antiepileptic drugs.
authors.affiliation: Centro Brasileiro de Serviços e Pesquisas em Proteínas, Departamento de Biologia Celular, Universidade de Brasília, CEP 70.910-900 Brasília, DF, Brazil.
authors.forename: Ricardo B
authors.initials: RB
authors.lastname: Cunha
authors.forename: Alfredo N C
authors.initials: AN
authors.lastname: Santana
authors.forename: Patrícia C
authors.initials: PC
authors.lastname: Amaral
authors.forename: Maria D F
authors.initials: MD
authors.lastname: Carvalho
authors.forename: Doris M F
authors.initials: DM
authors.lastname: Carvalho
authors.forename: Esper A
authors.initials: EA
authors.lastname: Cavalheiro
authors.forename: Bernard
authors.initials: B
authors.lastname: Maigret
authors.forename: Carlos A O
authors.initials: CA
authors.lastname: Ricart
authors.forename: Bruno A
authors.initials: BA
authors.lastname: Cardi
authors.forename: Marcelo V
authors.initials: MV
authors.lastname: Sousa
authors.forename: Krishnamurti M
authors.initials: KM
authors.lastname: Carvalho
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003064:Cnidarian Venoms / Q000737:chemistry* / Q000633:toxicity*; D004569:Electroencephalography / Q000187:drug effects*; D008297:Male; D008969:Molecular Sequence Data; D051381:Rats; D017208:Rats, Wistar; D012615:Sea Anemones; D012640:Seizures / Q000139:chemically induced*; D017386:Sequence Homology, Amino Acid
chemical_list: D003064:Cnidarian Venoms