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Effects of dopamine on porcine myocardial action potentials and contractions at 37 degrees C and 32 degrees C

Roscher, Roger LU ; Arlock, Per LU ; Sjöberg, Trygve LU and Steen, Stig LU (2001) In Acta Anaesthesiologica Scandinavica 45(4). p.421-426
Abstract
BACKGROUND: Little information exists on the effects of drugs with cardiovascular action in hypothermia, and some findings have indicated paradoxic effects of dopamine in this setting. As we have not found any data on the electrophysiologic and contractile effects of dopamine on the heart in hypothermia, we decided to study this in pig myocardium, since pigs have a cardiovascular system more similar to that of humans than other animals. METHODS: Excised muscle strips from pig ventricular septum were mounted in an organ bath. After 45 min of equilibration at 37 degrees C or 32 degrees C, resting and action potentials, time to peak contraction and contractile force were recorded during pacing with a frequency of 60/min. Dopamine at 4 microM... (More)
BACKGROUND: Little information exists on the effects of drugs with cardiovascular action in hypothermia, and some findings have indicated paradoxic effects of dopamine in this setting. As we have not found any data on the electrophysiologic and contractile effects of dopamine on the heart in hypothermia, we decided to study this in pig myocardium, since pigs have a cardiovascular system more similar to that of humans than other animals. METHODS: Excised muscle strips from pig ventricular septum were mounted in an organ bath. After 45 min of equilibration at 37 degrees C or 32 degrees C, resting and action potentials, time to peak contraction and contractile force were recorded during pacing with a frequency of 60/min. Dopamine at 4 microM or 8 microM was added and new recordings were made after 15 min. RESULTS: Cooling to 32 degrees C caused a prolongation of contraction by 48% and the contractile force increased by 39%. The membrane action potential duration at 50% and 90% repolarization levels increased at 32 degrees C by 28% and 16% respectively. Dopamine significantly (P<0.05) increased the contractile force and membrane action potential duration at 50% and 90% repolarization levels both in normothermia and in hypothermia, whereas the duration of the contraction was not significantly changed. CONCLUSION: Cooling to 32 degrees C significantly prolongs the myocardial action potential and the contraction duration. Dopamine increases the contractile force and prolongs the action potential both at 37 degrees C and at 32 degrees C. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Dopamine, hypothermia, inotropic drugs
in
Acta Anaesthesiologica Scandinavica
volume
45
issue
4
pages
421 - 426
publisher
Wiley-Blackwell
external identifiers
  • pmid:11300379
  • scopus:0035076618
ISSN
0001-5172
DOI
10.1034/j.1399-6576.2001.045004421.x
language
English
LU publication?
yes
id
e86a9b67-b2cc-410f-9590-644311609963 (old id 1122287)
date added to LUP
2008-07-14 08:29:20
date last changed
2018-05-29 09:40:05
@article{e86a9b67-b2cc-410f-9590-644311609963,
  abstract     = {BACKGROUND: Little information exists on the effects of drugs with cardiovascular action in hypothermia, and some findings have indicated paradoxic effects of dopamine in this setting. As we have not found any data on the electrophysiologic and contractile effects of dopamine on the heart in hypothermia, we decided to study this in pig myocardium, since pigs have a cardiovascular system more similar to that of humans than other animals. METHODS: Excised muscle strips from pig ventricular septum were mounted in an organ bath. After 45 min of equilibration at 37 degrees C or 32 degrees C, resting and action potentials, time to peak contraction and contractile force were recorded during pacing with a frequency of 60/min. Dopamine at 4 microM or 8 microM was added and new recordings were made after 15 min. RESULTS: Cooling to 32 degrees C caused a prolongation of contraction by 48% and the contractile force increased by 39%. The membrane action potential duration at 50% and 90% repolarization levels increased at 32 degrees C by 28% and 16% respectively. Dopamine significantly (P&lt;0.05) increased the contractile force and membrane action potential duration at 50% and 90% repolarization levels both in normothermia and in hypothermia, whereas the duration of the contraction was not significantly changed. CONCLUSION: Cooling to 32 degrees C significantly prolongs the myocardial action potential and the contraction duration. Dopamine increases the contractile force and prolongs the action potential both at 37 degrees C and at 32 degrees C.},
  author       = {Roscher, Roger and Arlock, Per and Sjöberg, Trygve and Steen, Stig},
  issn         = {0001-5172},
  keyword      = {Dopamine,hypothermia,inotropic drugs},
  language     = {eng},
  number       = {4},
  pages        = {421--426},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Anaesthesiologica Scandinavica},
  title        = {Effects of dopamine on porcine myocardial action potentials and contractions at 37 degrees C and 32 degrees C},
  url          = {http://dx.doi.org/10.1034/j.1399-6576.2001.045004421.x},
  volume       = {45},
  year         = {2001},
}