Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation
In rats, the nitric oxide (NO)-synthase pathway is present in skeletal muscle, vascular smooth muscle, and motor nerve terminals. Effects of NO were previously studied in rat neuromuscular preparations receiving low (0.2 Hz) or high (200 Hz) frequencies of stimulation. The latter frequency has alway...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Divulgação Científica
2001-06-01
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| Series: | Brazilian Journal of Medical and Biological Research |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000600020 |
| _version_ | 1819090598527762432 |
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| author | R.N. Queiroz Wilson Alves-Do-Prado |
| author_facet | R.N. Queiroz Wilson Alves-Do-Prado |
| author_sort | R.N. Queiroz |
| collection | DOAJ |
| description | In rats, the nitric oxide (NO)-synthase pathway is present in skeletal muscle, vascular smooth muscle, and motor nerve terminals. Effects of NO were previously studied in rat neuromuscular preparations receiving low (0.2 Hz) or high (200 Hz) frequencies of stimulation. The latter frequency has always induced tetanic fade. However, in these previous studies we did not determine whether NO facilitates or impairs the neuromuscular transmission in preparations indirectly stimulated at frequencies which facilitate neuromuscular transmission. Thus, the present study was carried out to examine the effects of NO in rat neuromuscular preparations indirectly stimulated at 5 and 50 Hz. The amplitude of muscular contraction observed at the end (B) of a 10-s stimulation was taken as the ratio (R) of that obtained at the start (A) (R = B/A). S-nitroso-N-acetylpenicillamine (200 µM), superoxide dismutase (78 U/ml) and L-arginine (4.7 mM), but not D-arginine (4.7-9.4 mM), produced an increase in R (facilitation of neurotransmission) at 5 Hz. However, reduction in the R value (fade of transmission) was observed at 50 Hz. N G-nitro-L-arginine (8.0 mM) antagonized both the facilitatory and inhibitory effects of L-arginine (4.7 mM). The results suggest that NO may modulate the release of acetylcholine by motor nerve terminals. |
| first_indexed | 2024-12-21T22:26:23Z |
| format | Article |
| id | doaj.art-d259ba767c804e28b7ba3a0d1d0ddce2 |
| institution | Directory Open Access Journal |
| issn | 0100-879X 1414-431X |
| language | English |
| last_indexed | 2024-12-21T22:26:23Z |
| publishDate | 2001-06-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-d259ba767c804e28b7ba3a0d1d0ddce22022-12-21T18:48:12ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2001-06-0134682582810.1590/S0100-879X2001000600020Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulationR.N. QueirozWilson Alves-Do-PradoIn rats, the nitric oxide (NO)-synthase pathway is present in skeletal muscle, vascular smooth muscle, and motor nerve terminals. Effects of NO were previously studied in rat neuromuscular preparations receiving low (0.2 Hz) or high (200 Hz) frequencies of stimulation. The latter frequency has always induced tetanic fade. However, in these previous studies we did not determine whether NO facilitates or impairs the neuromuscular transmission in preparations indirectly stimulated at frequencies which facilitate neuromuscular transmission. Thus, the present study was carried out to examine the effects of NO in rat neuromuscular preparations indirectly stimulated at 5 and 50 Hz. The amplitude of muscular contraction observed at the end (B) of a 10-s stimulation was taken as the ratio (R) of that obtained at the start (A) (R = B/A). S-nitroso-N-acetylpenicillamine (200 µM), superoxide dismutase (78 U/ml) and L-arginine (4.7 mM), but not D-arginine (4.7-9.4 mM), produced an increase in R (facilitation of neurotransmission) at 5 Hz. However, reduction in the R value (fade of transmission) was observed at 50 Hz. N G-nitro-L-arginine (8.0 mM) antagonized both the facilitatory and inhibitory effects of L-arginine (4.7 mM). The results suggest that NO may modulate the release of acetylcholine by motor nerve terminals.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000600020skeletal musclenitric oxideL-arginineneuromuscular transmissiontetanic fadeS-nitroso-N-acetylpenicillaminesuperoxide dismutase |
| spellingShingle | R.N. Queiroz Wilson Alves-Do-Prado Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation Brazilian Journal of Medical and Biological Research skeletal muscle nitric oxide L-arginine neuromuscular transmission tetanic fade S-nitroso-N-acetylpenicillamine superoxide dismutase |
| title | Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| title_full | Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| title_fullStr | Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| title_full_unstemmed | Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| title_short | Effects of L-arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| title_sort | effects of l arginine on the diaphragm muscle twitches elicited at different frequencies of nerve stimulation |
| topic | skeletal muscle nitric oxide L-arginine neuromuscular transmission tetanic fade S-nitroso-N-acetylpenicillamine superoxide dismutase |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001000600020 |
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