Tachyphylaxis and sensitization to nicotine-induced tachycardiac and pressor effects after nicotine infusions
Arch. med. res
; Arch. med. res;28(2): 189-94, jul. 1997. tab, ilus
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| LILACS
| ID: lil-225213
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RESUMO
This work examined the effects of nicotine on mean arterial pressure and heart rate in non-anesthetized as a single bolus, as infusions lasting 7.5, 15 or 30 min, and as a post-infusion bolus. A nicotine bolus increased pressure and rate. These effects were less marked as the rate of infusion decreased. The infusions affected differentially the effects of a subsequent bolus. Thus, while tachycardia was decreased, the blood pressure rise was increased. An initial transiet bradycardia was observed after bolus administration, but not during infusions; this effect was unchaged after post-infusion boluses. Pharmacological analysis indicated that tachycardia and bradycardia were predominantly due to ganglionic stimulation, while adrenal and sumpathetic nerve catecholamine release played a major role in the pressor response., These results indicate that slow nicotine infusions do not induce tachyphylaxis for all of the cardiovascular effects of a subsequent bolus, and that development of acute tolerance appears to depend on the mechanism of action of the response
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Indice:
LILACS
Sujet Principal:
Pression sanguine
/
Bradycardie
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Calendrier d'administration des médicaments
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Rat Wistar
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Rythme cardiaque
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Hypertension artérielle
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Injections veineuses
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Nicotine
Limites du sujet:
Animals
langue:
En
Texte intégral:
Arch. med. res
Thème du journal:
MEDICINA
Année:
1997
Type:
Article