Abstract
Purpose
The aims of the present studies were to determine whether the systemic hypotensive response to protamine was modified in rats pre-treated for two weeks with the nitric oxide synthase inhibitor, NG-nitro-L-argi-nine-methyl ester (L-NAME), and to evaluate the inhibitory effect of heparin on the systemic hypotensive response to protaminein vivo.
Methods
Male rats were randomly assigned into four groups. Normal saline 12μl·day−1, D-NAME (an inactive enantiomer of L-NAME), 10 mg·kg−1·day−1, L-NAME, 1 or 10 mg·kg−1·day−1 ip was administered for two weeks and the haemodynamic changes were measured after protamine administration. In another experiment, male rats were assigned to two groups. In one, the heparin group, protamine was administered after heparin had been administered and in the other, protamine group, protamine alone was administered.
Results
L-NAME inhibited the decrease in systemic arterial pressure after protamine administration (P < 0.05), but D-NAME had no effect. Also, heparin reduced the decrease in systemic arterial pressure after protamine (P < 0.05).
Conclusion
Nitric oxide is mainly responsible for mediation of the systemic hypotensive response to protamine which is also reduced by heparin.
Résumé
Objectif
L’objectif des présentes études était de déterminer si la réaction hypotensive généralisée à la protamine était modifiée chez les rats prétraités pendant deux semaines avec l’inhibiteur de l’oxyde nitrique synthase, NG-nitro-L-arginine-methyl ester (L-NAME), et d’évaluer l’effet inhibiteur de l’héparine sur la réaction hypotensive généralisée à la protamine,in vivo.
Méthode
Des rats mâles ont été répartis au hasard en quatre groupes. Une solution salée de 12 μl·jour−1, DNAME (un énantiomère inactif de L-NAME), 10 mg·kg−1·jour−1, L-NAME, 1 ou 10 mg·kg−1·jour−1 ip a été administré pendant deux semaines et les changements hémodynamiques ont été mesurés après l’administration de protamine. Lors d’une autre expérience, les rats ont été divisés en deux groupes. Dans l’un d’eux, le groupe héparine, l’administration de la protamine a suivi celle de l’héparine et, dans l’autre groupe, le groupe protamine, seule la protamine a été administrée.
Résultats
L-NAME a empêché la baisse de tension artérielle générale après l’administration de la protamine (P < 0,05), mais D-NAME n’a pas eu d’effet. De même, l’héparine a réduit la baisse de la tension artérielle générale après l’administration de protamine (P < 0,05).
Conclusion
Loxyde nitrique est principalement responsable de la médiation de la réaction hypotensive généralisée à la protamine, laquelle est aussi réduite par l’héparine.
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Komatsu, H., Enzan, K., Matsuura, S. et al. Systemic hypotensive response to protamine following chronic inhibition of nitric oxide synthase in rats. Can J Anaesth 45, 1186–1189 (1998). https://doi.org/10.1007/BF03012461
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DOI: https://doi.org/10.1007/BF03012461