Study of Pharmacological Effects of (O-Methyl)-N-2,6-dihydroxy-benzoyl-tyramine (riparin III) from Aniba riparia (Nees) Mez (Lauraceae) on behavioral models of anxiety and depression in mice / Estudo dos efeitos farmacolÃgicos de (O-METIL)-N-2,6-Dihidroxi-benzoil Tiramina (Riparina III) de Aniba Riparia (NEES) mez (Lauraceae) em modelos comportamentais de ansiedade e depressÃo em camundongos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Riparin III, an alkamide isolated from unripe fruit of Aniba riparia, was evaluated in animal classical models for screening of new drugs in anxiety, depression, sedation and convulsion, such as, open field, rota rod, plus maze, hole board, forced swimming, tail suspension, apomorphine-induced hypothermia, pentobarbital-induced sleeping time and pentilenotetrazole-induced seizures tests. Riparin III was administered acutely in all tests, at doses of 25 e 50 mg/kg, through oral and intraperitoneal routes. The results showed that this alkamide did not alter the locomotor activity, but decreased the number of rearing and grooming, in the open field test, suggesting a possible anxiolytic effect. In the plus maze and hole board tests, riparin III presented anxiolytic effect due to an increase in all parameters analyzed, such as, NEOA, PEOA, TPOA and PTOA, in the plus maze, and an increase in the number of head dips in the hole board test. This effect is possible related with GABAergic system, since flumazenil, an antagonist of GABAA/Benzodiazepinic receptors, reversed the anxiolytic effect of riparin III, in the plus maze test. The sedative/hypnotic evaluation of riparin III, in pentobarbital-induced sleeping time, showed a sleeping potentiation that seems to be involved with pharmacokinetic processes or sleeping regulation mechanisms, since the sedative effect of riparin III was not corroborated in the open field test. In the pentilenotetrazole-induced seizures test, riparin III partially protected the animals from seizures, increased the death time, and in some cases, even protected the animals from death. This result may suggest an anticonvulsant effect of riparin III, possible related to GABAergic system, since there is an involvement of this substance with GABAA/Benzodiazepinic receptor, seen in plus maze test. Riparin III also presents an antidepressant effect, since in the forced swimming and tail suspension tests, this substance decreased the immobility time of the animals. This antidepressant effect does not seem to be related with noradrenergic system, since in the apomorphine-induced hypothermia test, riparin III potentiated instead of antagonizing, the hypothermia. It is known that the hypothermia-antagonized effect is a characteristic of antidepressant drugs, such as imipramine-like drugs. This way, it can be eliminated the possible involvement of riparin III with noradrenergic system. On the other hand, the antidepressant effect of riparin III seems to be related with dopaminergic system, since the antagonist of D2 dopaminergic receptor, sulpiride, reverted riparin III effect in the forced swimming test. However, the antagonist of D1 dopaminergic receptor, SCH23390, did not revert this effect. This result suggests that the antidepressant effect of this alkamide is involved with dopaminergic system, specifically with D2 dopaminergic receptor. In conclusion, these efects showed that riparin III presents anxiolytic and anticonvulsant effects, probably related with GABAergic system, and presents antidepressant effect, probably related with dopaminergic system

ASSUNTO(S)

aniba riparia anxiolytic effect depressÃo aniba riparia alkamides modelos animais anticonvulsant effect riparin iii riparina iii alcamidas alcamidas poliinsaturadas - farmacologia farmacologia lauraceae - efeitos de drogas ansiedade tiramina - farmacologia efeito antidepressivo antidepressant effect efeito anticonvulsivante efeito ansiolÃtico

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