Effects of Vasoconstrictors Used in Local Anesthesia Upon Isolated Rat Heart

A Role for BK Channels in Heart Rate Regulation in Rodents

“…However, coronary flow remained constant throughout the isolated rat heart experiments, indicating that coronary resistance was constant, and therefore vasoconstriction did not occur. Furthermore, potent vasoconstrictors have little or no effect on heart rate in the isolated heart [55], [56], [57], suggesting that any inhibition of BK channels in coronary blood vessels would be unlikely to make a substantial contribution to the observed bradycardia.…”

Comparison of epinephrine and felypressin pressure effects in 1K1C hypertensive rats treated or not with atenolol

“…This suggests that vasoconstriction is the only mechanism to increase blood pressure in the felypressin experiments. Other studies have showed that felypressin significantly reduced cardiac rate in isolated rabbit heart at a dose of 1.6 IU, and reduced contraction force at a dose of 5.5 IU [19]; felypressin also increased cardiac arrest produced by prilocaine in isolated hearts [20]. Controlled hypertensive patients showed a higher diastolic pressure during periodontal treatment with prilocaine anesthesia associated with felypressin than with prilocaine alone [21].…”

Estudo dos efeitos da injeção intravascular de drogas vasoconstrictoras, presentes nas soluções anestésicas locais, sobre a pressão arterial de ratos normotensos, hipertensos renais um-rim, um clip (1R-1C) e 1R-1C tratados com atenolol

“…Maxwell (1965) descrevendo os efeitos cardiovasculares "in vivo" da felipressina em coração de cão, também já havia notado efeito inotrópico e cronotrópico negativo. A hipótese também levantada por Oliveira (2002) para explicar os efeitos cronotrópicos e inotrópicos negativos, toma por base o trabalho de Agata et al (1999), que mostra redução de fluxo sanguíneo coronariano e diminuição da tensão tissular de oxigênio durante anestesia, em cães.…”