Pharmacological Modulation of Hemodynamics in Adult Zebrafish In Vivo

Abstract

IntroductionHemodynamic parameters in zebrafish receive increasing attention because of their important role in cardiovascular processes such as atherosclerosis, hematopoiesis, sprouting and intussusceptive angiogenesis. To study underlying mechanisms, the precise modulation of parameters like blood flow velocity or shear stress is centrally important. Questions related to blood flow have been addressed in the past in either embryonic or ex vivo-zebrafish models but little information is available for adult animals. Here we describe a pharmacological approach to modulate cardiac and hemodynamic parameters in adult zebrafish in vivo.Materials and MethodsAdult zebrafish were paralyzed and orally perfused with salt water. The drugs isoprenaline and sodium nitroprusside were directly applied with the perfusate, thus closely resembling the preferred method for drug delivery in zebrafish, namely within the water. Drug effects on the heart and on blood flow in the submental vein were studied using electrocardiograms, in vivo-microscopy and mathematical flow simulations.ResultsUnder control conditions, heart rate, blood flow velocity and shear stress varied less than ± 5%. Maximal chronotropic effects of isoprenaline were achieved at a concentration of 50 μmol/L, where it increased the heart rate by 22.6 ± 1.3% (n = 4; p < 0.0001). Blood flow velocity and shear stress in the submental vein were not significantly increased. Sodium nitroprusside at 1 mmol/L did not alter the heart rate but increased blood flow velocity by 110.46 ± 19.64% (p = 0.01) and shear stress by 117.96 ± 23.65% (n = 9; p = 0.03).DiscussionIn this study, we demonstrate that cardiac and hemodynamic parameters in adult zebrafish can be efficiently modulated by isoprenaline and sodium nitroprusside. Together with the suitability of the zebrafish for in vivo-microscopy and genetic modifications, the methodology described permits studying biological processes that are dependent on hemodynamic alterations.

The Effect of Hypothermia and Osmotic Shock on the Electrocardiogram of Adult Zebrafish

“…It is apparent that the choice of technique has a major influence on the raw ECG signal. For example, by using the non-invasive technique it appears that Q, S, and T waves are difficult to identify [17,19], and are generally assigned manually after the raw data has been processed [18]. In contrast, by using electrodes that allow direct access to the hearts electrical activity it is possible to reliably identify P waves, the Q, R, S complex, and T waves [2][3][4][5]23,26,27].…”

Characterization of the adult zebrafish electrocardiogram

“…It is apparent from our own (and others [9,10]) research that recording adult zebrafish T waves is inherently difficult and susceptible to operator bias. Indeed, in the unexposed heart configuration we could barely detect any T waves at all.…”

“…It is apparent that the choice of technique has a major influence on the raw ECG signal. For example, using the non-invasive technique it appears that Q, S and T waves are difficult to identify [9,11], and are generally assigned manually after the raw data has been processed [10]. In contrast, by using electrodes that allow direct access to the hearts electrical activity it is possible to reliably identify P waves, the Q, R, S complex and T waves [2][3][4][5]15,18,19].…”

“…Currently, there are two different techniques used by research teams to record ECG in adult zebrafish hearts. The first is non-invasive and involves positioning the electrodes on the body surface [9][10][11], while the second technique involves inserting the electrodes either 1mm into the dermis (i.e. in the pectoral muscles) or directly onto the surface of an exposed heart [1,[3][4][5][12][13][14][15][16][17][18].…”

CRISPR/Cas9‐induced nos2b mutant zebrafish display behavioral abnormalities

“…To verify the link among NO, expression of synaptophysin and homer1 , and behavior, we treated zebrafish with SNP/MPH. Due to its characteristics of efficiently decomposing and releasing NO, SNP has been widely used as a NO donor and applied in zebrafish research 51‐53 . MPH can increase the concentration of neurotransmitters in the synaptic cleft by inhibiting the recycling of neurotransmitters.…”