EFFECTS OF VASOCONSTRICTORS USED IN LOCAL ANESTHESIA UPON ISOLATED RAT HEART

• Published in: Pharmacological research 2002-07, Vol.46 (1), p.15-18
• Main Authors: OLIVEIRA, N.S, GAZOLA, R, SINGI, G
• Format: Article
• Language: English
• Subjects: Anesthetics, Local - pharmacology; Animals; Dose-Response Relationship, Drug; epinephrine; Epinephrine - pharmacology; felypressin; Felypressin - pharmacology; Heart - drug effects; Heart - physiology; In Vitro Techniques; isolated rat heart; Male; Myocardial Contraction - drug effects; Myocardial Contraction - physiology; Rats; Rats, Wistar; Vasoconstrictor Agents - pharmacology
• ISSN: 1043-6618; 1096-1186
• DOI: 10.1016/S1043-6618(02)00074-9

Some reports have demonstrated that the vasoconstrictor effect of catecholamines may be amplified by felypressin. Thus, the association of felypressin and epinephrine with local anesthetics may be indicated to achieve more effective vasoconstrictor actions with fewer collateral effects from both the anesthetic and the vasoconstrictor. This study aimed to characterize the effects of felypressin and associations of felypressin and epinephrine upon the contraction force and the cardiac rate of the isolated rat heart ( n=20) perfused by Langendorff’s method. The following solutions were utilized: epinephrine, 4.5 nmol; felypressin at doses of 0.5, 1.6 and 5.5 IU and associations of felypressin at the same doses with 4.5 nmol epinephrine. Contraction force and cardiac rate were recorded at 15, 30, 60 and 120 s after the administration of each solution, and before the administration, a control measurement (time 0) was taken. Felypressin at a dose of 0.5 IU did not have any effect upon the heart, but the doses of 1.6 and 5.5 IU decreases the cardiac rate and the contraction force, respectively. Epinephrine and all of the felypressin and epinephrine associations produced increases in these parameters. The association of 0.5 IU felypressin and 4.5 nmol epinephrine promoted a similar effect to that of epinephrine (4.5 nmol) alone up to 120 s. The association of 1.6 IU felypressin and 4.5 nmol epinephrine increases the contraction force up to 60 s. After the administration of the association of 5.5 IU felypressin and 4.5 nmol epinephrine this increase was observed up to just 30 s. The cardiac rate values obtained after the administration of the associations of 1.6 and 5.5 IU felypressin with 4.5 nmol epinephrine were lower than those seen after the use of 4.5 nmol epinephrine alone. In this study it was observed that the association of felypressin with epinephrine decreased the effects of epinephrine which increases the cardiac rate and the contraction force in the isolated rat heart.