Navegando por Palavras-chave "Bicuculline"

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    Anticonvulsant and GABA uptake inhibition properties of venom fractions from the spiders Parawixia bistriata and Scaptocosa raptoria
    (Swets Zeitlinger Publishers, 2002-09-01) Rodrigues, Marcelo Cairrão Araujo; Ribeiro, Alessandra Mussi; Pizzo, Andrea Baldocchi; Fontana, Andreia Cristina Karklin; Beleboni, Renê de Oliveira; Coutinho-Netto, Joaquim; Miranda, Antonio de [UNIFESP]; Santos, Wagner Ferreira dos; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    In this article we describe an in vivo anticonvulsant effect from denatured crude venom and partially isolated fractions from two spiders: Parawixia bistriata and Scaptocosa raptoria. Intracerebroventricular injections of these venoms and fractions abolished rat convulsive tonic-clonic seizures induced by picrotoxin, bicuculline and pentylenetetrazole, and also, inhibited GABA uptake in synaptosomes of rat cerebral cortex. the venoms described in this work seems to be promising tools for the study of the GABAergic system, and may be a potential source for new anticonvulsant drugs.
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    A anticonvulsive fraction from Scaptocosa raptoria (Araneae : Lycosidae) spider venom
    (Elsevier B.V., 2004-11-23) Ribeiro, Alessandra Mussi; Miranda, Antonio [UNIFESP]; Gobbo-Netto, Leonardo; Lopes, Norberto Peporine; Santos, Wagner Ferreira dos; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    Several spider neurotoxins are known to show highly selective effects on nervous tissues. Intracerebral injection into rats of spider venom from Scaptocosa raptoria, prevents seizures induced by convulsant agents. Injection of phenytoin (390 pmol/200 nl), muscimol (90 pmol/200 nl), baclofen (500 pmol/200 nl) into the substantia nigra (SN) pars reticulata, protected rats from convulsions evoked by unilateral focal injection of bicuculline into the area tempestas by 50, 80, and 100%, respectively. Denatured S. raptoria crude venom (4.6 mug, 2.3 mug, and 920 ng/200 nl), when administered into the SN, prevented seizures elicited by bicuculline in the area tempestas by 100, 100, and 87.5%, respectively. the injection into the SN of 160 ng/200 nl of fraction SrTx1 isolated from S. raptoria venom, reduced the magnitude of seizures. This fraction was rechromatographed affording fractions SrTx1.1, SrTx1.2 and SrTx1.3, and they were administered into the SN at doses of 100, 200, and 400 ng/200 nl respectively. Fraction SrTx1.3 protected 50, 85.7, and 100% of the animals against the seizures elicited by bicuculline injected into the area tempestas. This suggests that S. raptoria venom as well as its SrTx1.3 fraction, might be potential sources of new anticonvulsant drugs. (C) 2004 Elsevier Ireland Ltd. All rights reserved.
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    Efeito do pentobarbital e bicuculina sobre a concentração de gangliosídeos no córtex cerebral de ratos
    (Universidade Federal de São Paulo (UNIFESP), 1991) Vital, Maria Aparecida Barbato Frazão [UNIFESP]; Trolin, Cecília Gomes [UNIFESP]
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    Putative pathways involved in cardiovascular-responses evoked from the caudal presser area
    (Assoc Bras Divulg Cientifica, 1994-10-01) Campos, Ruy Ribeiro [UNIFESP]; Pôssas, Olga Sueli [UNIFESP]; Cravo, Sergio Luiz [UNIFESP]; Lopes, Oswaldo Ubriaco [UNIFESP]; Guertzenstein, Pedro Gaspar [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    1. The caudal presser area (CPA) is a recently identified site within the ventrolateral medulla which is involved in cardiovascular regulation. CPA chemical stimulation by L-glutamate produces an increase in arterial blood pressure (ABP) while its inhibition by GABA or glycine evokes marked hypotension. In the present study, we sought to determine the potential neural pathways underlying these responses.2. In urethane-anesthetized, paralyzed, artificially ventilated rats, CPA inhibition by bilateral microinjection of the inhibitory amino acid glycine (Gly, 100 nmol 200 nl(-1) site(-1)) produced an average decrease of -38 +/- 4.3 mmHg in ABP (N = 6). Ten min after bilateral microinjection of the broad-spectrum glutamate antagonist kynurenic acid (KYN, 2 nmol 200 nl(-1) site(-1)) into the caudal ventrolateral medulla (CVLM) depressor responses to CPA inhibition were virtually abolished (-3 +/- 1.7 mmHg, P<0.05). Similar microinjection of KYN into the rostral ventrolateral medulla (RVLM) or into the CPA itself did not modify depressor responses to CPA inhibition by glycine.3. CPA stimulation by bilateral microinjection of the excitatory amino acid L-glutamate (L-glu, 50 nmol 200 nl(-1) site(-1)) produced an increase in ABP (+43 +/- 5.4 mmHg, N = 6). Bilateral microinjection of the GABA A antagonist bicuculline methiodide (BIC, 200 pmol 200 nl(-1) site(-1)). into the CVLM markedly reduced presser responses to CPA stimulation (+6 +/- 2.7 mmHg, P<0.05). similar application of BIC into the RVLM or CPA did not modify presser responses to CPA stimulation by glutamic acid.4. These results demonstrate that cardiovascular responses to CPA excitation or inhibition are mediated by the CVLM, and that glutamatergic and GABAergic synapses are involved. We conclude that CPA acts by modulating the sympathoinhibitory function of the caudal ventrolateral medulla.