Ação ansiolítica e anticonvulsivante da 6-Esteril-2-Pirona de Aniba panurensis em camundongos : possível mecanismo de ação

Abstract

The genus Aniba stands out for its pharmacological properties, such as anxiolytic, antidepressant and vasorelaxant. Of the Aniba panurensis fruits popularly known as ―louro amarelo‖ a natural pyrone, 6-[(E)-styryl-pyran-2-one], was identified. The objective of this study was to verify the neuropharmacological effects of 6-[(E)-styryl-pyran-2-one] (STY), obtained from Aniba panurensis, in mice through behavioral tests (spontaneous locomotor activity (SLA), rearing and grooming), tests of chemically induced seizures and neurochemical dosages of amino acids (glutamate (GLU), aspartate (ASP), γ-aminobutyric acid (GABA), glycine (GLY), taurine (Tau), histidine (HIS) in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST). We used Swiss mice, male, with an average weight of 28 grams. The animals were treated with a single dose of STY (1, 5, 10 or 20 mg) by intraperitoneal injection. Thirty minutes after administration, the animals were subjected to behavioral tests of chemically induced seizures by pentylenetetrazol (PTZ), strychnine, bicuculline and pilocarpine. Immediately after the tests, the animals were sacrificed and the brain areas of interest were dissected to estimate the amino acid concentration via HPLC (High Performance Liquid Chromatography). In the SLA test the STY at 10 or 20 mg/kg dose increased locomotor activity when compared to the control group. In the elevated plus-maze and hole-board tests, the STY in all doses proved its anxiolytic effect, because it increased all parameters analyzed. In the dosage of amino acid neurotransmitters after behavioral test there was an increase in inhibitory amino acid concentrations (GABA, GLY, TAU, HIS) and excitatory (ASP, GLU) in PFC, HC and ST. After pretreatment with STY, the animals were tested for seizures induced by PTZ (85 mg/kg) or Bicuculline (12 mg/kg), we observed an increase in the latency of seizures and death in surviving animals at the highest dose. During the strychnine-induced seizures test (20 mg/kg) there was an increase in seizure latency (STY-10: 50.42 ± 7.20; STY-20: 65.99 ± 3.22) and latency to death (STY-1: 20 ± 1.72; STY-10: 19.17 ± 1.87; STY-20: 23.83 ± 1.55) in all animals pretreated with STY. In the pilocarpine-induced seizures there was a decrease in the latency to death. After testing the animals, we conducted the dosage of amino acid concentrations (ASP, GLU, GLY, TAU and GABA). PFC increased ASP, TAU and GABA. HC increased GLU, ASP, GLY and GABA. In the strychnine-induced seizure in PFC there was an increase in ASP, TAU and GABA, while the HC increased ASP, GLY, TAU and GABA. In the bicuculline-induced seizure in PFC there was an increase in ASP, GLU, GLY, TAU and GABA, while the HC increased ASP, GLU, GLY, TAU and GABA. In the pilocarpine-induced seizure in PFC there was an increase in ASP, GABA, GLY, while the HC increased only ASP. We concluded that STY presents an anxiolytic effect in behavioral tests and a protective effect in tests of induced seizures by PTZ, strychnine and bicuculline. After the dosage of the amino acids we can demonstrate the involvement of glutamatergic, GABAergic and glycinergic systems.