title: Expression and localization of an agmatinase-like protein in the rat brain.
abstract: Agmatinase catalyzes the hydrolysis of agmatine into putrescine and urea, and agmatine (decarboxylated L: -arginine) plays several roles in mammalian tissues, including neurotransmitter/neuromodulatory actions in the brain. Injection of agmatine in animals produces anticonvulsant, antineurotoxic and antidepressant-like actions. Information regarding the enzymatic aspects of agmatine metabolism in mammals, especially related to its degradation, is relatively scarce. The explanation for this is the lack of enzymatically active preparations of mammalian agmatinase. Recently, we have cloned a protein from a cDNA rat brain library having agmatinase activity although its amino acid sequence greatly differs from all known agmatinases, we called agmatinase-like protein. In this work, we analyzed the expression of this enzyme in the rat brain by means of RT-PCR and immunohistochemical analysis using a polyclonal antibody generated against the recombinant agmatinase-like protein. The agmatinase-like protein was detected in the hypothalamus in glial cells and arcuate nucleus neurons, and in hippocampus astrocytes and neurons, but not in brain cortex. In general, detected localization of agmatinase-like protein coincides with that described for its substrate agmatine and our results help to explain several reported effects of agmatine in the brain. Concretely, a role in the regulation of intracellular concentrations of the neurotransmitter/neuromodulator agmatine is suggested for the brain agmatinase-like protein.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mella
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez
authors.forename: María
authors.initials: M
authors.lastname: de Los Angeles García
authors.forename: Francisco
authors.initials: F
authors.lastname: Nualart
authors.forename: Víctor
authors.initials: V
authors.lastname: Castro
authors.forename: Paulina
authors.initials: P
authors.lastname: Bustos
authors.forename: Nelson
authors.initials: N
authors.lastname: Carvajal
authors.forename: Elena
authors.initials: E
authors.lastname: Uribe
mesh_terms: D000376:Agmatine / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D007031:Hypothalamus / Q000201:enzymology; D009457:Neuroglia / Q000201:enzymology; D051381:Rats; D011994:Recombinant Proteins / Q000032:analysis; D014018:Tissue Distribution; D014512:Ureohydrolases / Q000032:analysis*
chemical_list: D011994:Recombinant Proteins; D000376:Agmatine; D014512:Ureohydrolases; C019625:agmatinase