Neutralization of snake venom phospholipase A(2) toxins by aqueous extract of Casearia sylvestris (Flacourtiaceae) in mouse neuromuscular preparation

Aqueous extract of Casearia sylvestris (Flacourtiaceae) has been shown to inhibit enzymatic and biological properties of some Bothrops and Crotalus venoms and their purified phospholipase A(2) (PLA(2)) toxins. In this work we evaluated the influence of C sylvestris aqueous extract upon neuromuscular blocking and muscle damaging activities of some PLA(2)S (crotoxin from C. durissus terrificus, bothropstoxin-I from B.jararacussu, piratoxin-I from B. pirajai and myotoxin-II from B. moojeni) in mouse phrenic-diaphragm preparations. Crotoxin (0.5 mu M) and all other PLA2 toxins (1.0 mu M) induced irreversible and time-dependent blockade of twitches. Except for crotoxin, all PLA2 toxins induced significant muscle damage indices, assessed by microscopic analysis. Preincubation of bothropstoxin-I, piratoxin-I or myotoxin-II with C. sylvestris extract (1:5 (w/w), 30 min, 37 degrees C significantly prevented the neuromuscular blockade of preparations exposed to the mixtures for 90 min; the extent of protection ranged from 93% to 97%. The vegetal extract also neutralized the muscle damage (protection of 80-95%). Higher concentration of the C. sylvestris extract (1: 10, w/w) was necessary to neutralize by 90% the neuromuscular blockade induced by crotoxin. These findings expanded the spectrum of C. sylvestris antivenom activities, evidencing that it may be a good source of potentially useful PLA2 inhibitors. (c) 2007 Elsevier B.V.. All rights reserved.

Co-60 gamma irradiation prevents Bothrops jararacussu venom neurotoxicity and myotoxicity in isolated mouse neuromuscular junction

The ability of gamma radiation from Co-60 (2000 Gy) to attenuate the toxic effects of Bothrops jararacussu venom was investigated on mouse neuromuscular preparations in vitro. A comparative study between the effects of native and irradiated venoms was performed on both phrenic-diaphragm (PD) and extensor digitorum longus (EDL) preparations by means of myographic, biochemical and morphological techniques. Native venom (10 and 20 mug/ml) induced a concentration-dependent paralysis of both directly and indirectly evoked contractions on PD preparations. At 20 mug/ml, it also caused a pronounced myotoxic effect on the EDL muscle preparation that was characterized by an increase of creatine kinase release and by several morphological changes of this preparation. By contrast, irradiated venom, even at concentrations as high as 40 mug/ml, induced neither paralyzing nor myotoxic effects. It was concluded that Co-60 gamma radiation is able to abolish both the paralyzing and the myotoxic effects of B. jararacussu venom on the mouse neuromuscular junction. These findings support the hypothesis that gamma radiation could be an important toot to improve antisera production by reducing toxicity while preserving immunogenicity. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Morphological aspects of neuromuscular junctions and gene expression of nicotinic acetylcholine receptors (nAChRs) in skeletal muscle of rats with heart failure

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Acute neuromuscular manifestations in a patient associated with ingesting octopus (Octopus sp.)

Os autores relatam um quadro manifestado por sintomas neurológicos e musculares em uma mulher de 45 anos, que surgiu após o consumo da carne de polvo comum (Octopus sp.). A paciente apresentou intenso mal estar, parestesias em extremidades e área perioral, fraqueza muscular intensa e hipotensão arterial, seguidos de prurido importante e uma erupção eritêmato-descamativa disseminada tardia. Não foram observadas manifestações gastrintestinais ou febre, o que reduziu a probabilidade de uma intoxicação alimentar por conservação inadequada do molusco. A presença de sintomas neuro-musculares é sugestiva de ação de neurotoxinas, comprovadamente existentes em muitos gêneros de polvos e que podem ter sido ingeridas através do consumo das glândulas salivares ou acúmulo das toxinas na carne, por algum mecanismo ainda desconhecido. As toxinas dos polvos do gênero Octopus são pouco estudadas e julgamos esta comunicação importante por alertar para a possibilidade do envenenamento nos seres humanos que consomem carne de polvos e ainda sua diferenciação das intoxicações alimentares que ocorrem por conservação inadequada do animal.

The neurotoxicological effects of mastoparan Polybia-MPII at the murine neuromuscular junction: an ultrastructural and immunocytochemical study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de um programa de treinamento de facilitação neuromuscular proprioceptiva sobre a mobilidade torácica

A proposta deste estudo foi analisar o efeito de um programa de treinamento de membros superiores baseado nas técnicas de facilitação neuromuscular proprioceptiva (FNP) sobre a mobilidade torácica. Foram estudadas 24 voluntárias sedentárias, idade 22,9 ± 2,9 anos, divididas em grupo controle (GC), que não participou do treinamento, e grupo treinado (GT). O protocolo de treinamento físico foi constituído por um programa de exercícios de FNP, realizado três vezes por semana, durante quatro semanas. Os dois grupos foram submetidos à avaliação da mobilidade torácica por meio de cirtometria, antes e após o período de treinamento. Os dados colhidos foram analisados estatisticamente, com nível de significância α = 5%. Os valores da cirtometria axilar e xifoideana do GC antes e após o período de intervenção não apresentaram alterações significativas (p>0,05). No GT os valores das variáveis foram significantemente maiores após a intervenção (p<0,05). em conclusão, o protocolo de FNP utilizado parece ser um programa de exercícios eficiente, por promover aumento na cirtometria em um curto período de tempo, sugerindo que pode ser utilizado como recurso fisioterapêutico para o desenvolvimento da mobilidade torácica.

PHYSIOLOGICAL and NEUROMUSCULAR PROFILE DURING A BODYPUMP SESSION: ACUTE RESPONSES DURING A HIGH-RESISTANCE TRAINING SESSION

Oliveira, AS, Greco, CC, Pereira, MP, Figueira, TR, de Araujo Ruas, VD, Goncalves, M, and Denadai, BS. Physiological and neuromuscular profile during a Bodypump session: acute responses during a high-resistance training session. J Strength Cond Res 23(2): 579-586, 2009-The main purposes of this study were 1) to describe and to compare blood lactate ([La]), heart rate (HR), and electromyographic (EMG) parameters during high-repetition training sessions (HRTSs), 2) to analyze the influence of physical fitness levels in these parameters, and, 3) to analyze the relationship between metabolic ([La]) and neuromuscular (EMG) responses during the HRTS. Fifteen healthy untrained women (21.7 +/- 2.1 years) performed an HRTS called Bodypump for 1 hour, which incorporated the use of variable free weights and high repetitions in a group setting. This session involved 10 music selections (M1-M10) containing resistive exercises for different muscle groups. After music selections 2 (M2), 4 (M4), 6 (M6), 7 (M7), and 9 (M9), [La], HR, and EMG (vastus medialis [VM], vastus lateralis [VL], iliocostalis lumborum [IC], and longissimus thoracis <) were determined. The [La] (M2, 4.00 +/- 1.45 mM; M7, 5.02 +/- 1.73 mM) and HR (M2, 153.64 +/- 18.89 bpm; M7, 16.14 +/- 20.14 bpm) obtained at M2 and M7 were similar but were significantly higher than the other moments of the session. However, EMG (root mean square [RMS]) at M2 (VL, VM, and LT) was lower than at M7. There was no significant correlation of strength and aerobic physical fitness with [La], RMS. In the same way, there was no significant correlation of [La] with RMS at M2 and M7. on the basis of our data, we can conclude that metabolic, cardiovascular, and EMG variables present different and independent behavior during an HRTS. Accordingly, for neuromuscular conditions during HRTS, it seems to be enough to induce improvement in the muscular strength of inferior limbs in untrained subjects.

Effects of a single habituation session on neuromuscular isokinetic profile at different movement velocities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

IMPROVEMENTS IN METABOLIC and NEUROMUSCULAR FITNESS AFTER 12-WEEK BODYPUMP (R) TRAINING

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of neuromuscular electrical stimulation, laser therapy and LED therapy on the masticatory system and the impact on sleep variables in cerebral palsy patients: a randomized, five arms clinical trial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of nandrolone decanoate on the neuromuscular junction of rats submitted to swimming

This study addressed the effects of nandrolone decanoate (ND) on contractile properties and muscle fiber characteristics of rats submitted to swimming. Male Wistar rats were grouped in sedentary (S), swimming (Sw), sedentary+ND (SND), and swimming+ND (SwND), six animals per group. ND (3 mg/kg) was injected (subcutaneously) 5 days/week, for 4 weeks. Swimming consisted of 60-min sessions (load 2%), 5 days/week, for 4 weeks. After this period, the sciatic nerve extensor digitorum longus (EDL) muscle was isolated for myographic recordings. Fatigue resistance was assessed by the percent (%) decline of 180 direct tetanic contractions (30 Hz). Safety margin of synaptic transmission was determined from the resistance to the blockade of indirectly evoked twitches (0.5 Hz) induced by pancuronium (5 to 9 x 10(-7) M). EDL muscles were also submitted to histological and histochemical analysis (haematoxylin-eosin (HE); nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR)). Significant differences were detected by two-way ANOVA (p<0.05). ND did not change body mass, fatigue resistance or kinetic properties of indirect twitches in either sedentary or swimming rats. In contrast, ND reduced the safety margin of synaptic transmission in sedentary animals (SND=53.3+/-4.7% vs. S=75.7+/-2.0%), but did not affect the safety margin in the swimming rats (SwND=75.81+/-3.1% vs. Sw=71.0+/-4.0%). No significant difference in fiber type proportions or diameters was observed in EDL muscle of any experimental group. These results indicate that ND does not act as an ergogenic reinforcement in rats submitted to 4 weeks of swimming. on the other hand, this study revealed an important toxic effect of ND, that it reduces the safety margin of synaptic transmission in sedentary animals. Such an effect is masked when associated with physical exercise. (C) 2004 Elsevier B.V. All rights reserved.