Development of the sympatho-vagal balance in the cardiovascular system in zebrafish (Danio rerio) characterized by power spectrum and classical signal analysis

SUMMARY The development of sympatho-vagal control of cardiac activity was analyzed in zebrafish (Danio rerio) larvae from 2 to 15 days post fertilization (d.p.f.) by pharmacological studies as well as by assessing short term heart rate variability. Changes in heart rate in response to cholinergic and adrenergic receptor stimulation or inhibition were investigated using in situ preparations and digital video-microscopic techniques. The data revealed that the heart responded to adrenergic stimulation starting at 4 d.p.f. and to cholinergic stimulation starting at 5 d.p.f. Atropine application resulted in an increase in heart rate beyond 12 d.p.f., while the inhibitory effect of cholinergic stimulation ceased at this time of development. Adrenergic inhibition (propranolol) reduced heart rate for the first time at 5 d.p.f., but the reduction was only very small (3.8%). Between 5 and 12 d.p.f. propranolol application always resulted in a minor reduction in heart rate, but because the effect was so small it was not always significant. Because the presence of an adrenergic or cholinergic tone may influence the stability of heart rate, we analyzed short-term heart rate variability (HRV). The frequency band width of heart rate variability revealed that HRV increased between 4 d.p.f. and 15 d.p.f. From 13 to 15 d.p.f. atropine reduced the frequency band width of HRV, whereas the combination of atropine and propranolol effectively reduced the frequency band width between 11 and 15 d.p.f. Classical power spectrum analysis using electrocardiograms is not possible in tiny zebrafish larvae and juveniles. It was therefore performed using optical methods, recording cardiac movement and cardiotachograms calculated from these measurements. Whereas heart movements contained frequency components characterizing HRV, the cardiotachogram did not show typical frequency spectra as known from other species.

[1]  B. Pelster,et al.  Disruption of hemoglobin oxygen transport does not impact oxygen-dependent physiological processes in developing embryos of zebra fish (Danio rerio). , 1996, Circulation research.

[2]  B. Pelster,et al.  Temperature-dependent development of cardiac activity in unrestrained larvae of the minnow Phoxinus phoxinus. , 2000, American journal of physiology. Regulatory, integrative and comparative physiology.

[3]  Peter Rombough,et al.  Gills are needed for ionoregulation before they are needed for O(2) uptake in developing zebrafish, Danio rerio. , 2002, The Journal of experimental biology.

[4]  Hastings,et al.  Developmental changes in oxygen consumption regulation in larvae of the South African clawed frog Xenopus laevis , 1995, The Journal of experimental biology.

[5]  B. Pelster,et al.  Nitric oxide and vascular reactivity in developing zebrafish, Danio rerio. , 2000, American journal of physiology. Regulatory, integrative and comparative physiology.

[6]  T. Schwerte,et al.  Late onset of NMDA receptor-mediated ventilatory control during early development in zebrafish (Danio rerio). , 2006, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology.

[7]  J Altimiras,et al.  Is the short-term modulation of heart rate in teleost fish physiologically significant? Assessment by spectral analysis techniques. , 1995, Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas.

[8]  J Altimiras,et al.  Understanding autonomic sympathovagal balance from short-term heart rate variations. Are we analyzing noise? , 1999, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology.

[9]  M. Axelsson,et al.  Cholinergic and adrenergic influence on the teleost heart in vivo. , 1987, Experimental biology.

[10]  B. Pelster,et al.  Digital motion analysis as a tool for analysing the shape and performance of the circulatory system in transparent animals. , 2000, The Journal of experimental biology.

[11]  Thorsten Schwerte,et al.  Non-invasive imaging of blood cell concentration and blood distribution in zebrafish Danio rerio incubated in hypoxic conditions in vivo , 2003, Journal of Experimental Biology.

[12]  L. Protas,et al.  Ontogeny of cholinergic and adrenergic mechanisms in the frog (Rana temporaria) heart. , 1992, The American journal of physiology.

[13]  C. Liao,et al.  Zebrafish M2 muscarinic acetylcholine receptor: cloning, pharmacological characterization, expression patterns and roles in embryonic bradycardia , 2002, British journal of pharmacology.

[14]  T. Schwerte,et al.  Understanding cardiovascular physiology in zebrafish and Xenopus larvae: the use of microtechniques. , 2003, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology.

[15]  B. Pelster,et al.  Influence of hypoxia and of hypoxemia on the development of cardiac activity in zebrafish larvae. , 2002, American journal of physiology. Regulatory, integrative and comparative physiology.

[16]  E. Taylor,et al.  The use of power spectral analysis to determine cardiorespiratory control in the short-horned sculpin Myoxocephalus scorpius , 2004, Journal of Experimental Biology.

[17]  M. Fishman,et al.  Defective "pacemaker" current (Ih) in a zebrafish mutant with a slow heart rate. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[18]  C. Nüsslein-Volhard,et al.  Left-right pattern of cardiac BMP4 may drive asymmetry of the heart in zebrafish. , 1997, Development.

[19]  P C Hou,et al.  Cardiac output and peripheral resistance during larval development in the anuran amphibian Xenopus laevis. , 1995, The American journal of physiology.

[20]  D Jordan,et al.  Central control of the cardiovascular and respiratory systems and their interactions in vertebrates. , 1999, Physiological reviews.