title: Effects of GABA, Neural Regulation, and Intrinsic Cardiac Factors on Heart Rate Variability in Zebrafish Larvae.
abstract: Heart rate (HR) is a periodic activity that is variable over time due to intrinsic cardiac factors and extrinsic neural control, largely by the autonomic nervous system. Heart rate variability (HRV) is analyzed by measuring consecutive beat-to-beat intervals. This variability can contain information about the factors regulating cardiac activity under normal and pathological conditions, but the information obtained from such analyses is not yet fully understood. In this article, HRV in zebrafish larvae was evaluated under normal conditions and under the effect of substances that modify intrinsic cardiac activity and cardiac activity modulated by the nervous system. We found that the factors affecting intrinsic activity have negative chronotropic and arrhythmogenic effects at this stage of development, whereas neural modulatory factors have a lesser impact. The results suggest that cardiac activity largely depends on the intrinsic properties of the heart tissue in the early stages of development and, to a lesser extent, in the maturing nervous system. We also report, for the first time, the influence of the neurotransmitter gamma amino butyric acid on HRV. The results demonstrate the larval zebrafish model as a useful tool in the study of intrinsic cardiac activity and its role in heart diseases.
authors.affiliation: Departamento de Ciencias Fisiológicas, Facultad de Medicina, Pontificia Universidad Javeriana , Bogotá, Colombia .
authors.forename: Rafael Antonio
authors.initials: RA
authors.lastname: Vargas
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology*; D002492:Central Nervous System Depressants / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D018679:Cholinergic Agonists / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology*; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D006321:Heart / Q000187:drug effects* / Q000294:innervation*; D006339:Heart Rate / Q000187:drug effects*; D007814:Larva; D008012:Lidocaine / Q000494:pharmacology; D016210:Methacholine Chloride / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009118:Muscimol / Q000494:pharmacology; D015027:Zebrafish; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D002492:Central Nervous System Depressants; D000697:Central Nervous System Stimulants; D018679:Cholinergic Agonists; D015259:Dopamine Agents; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D018721:Muscarinic Agonists; D016210:Methacholine Chloride; D009118:Muscimol; D002110:Caffeine; D000431:Ethanol; D005680:gamma-Aminobutyric Acid; D008012:Lidocaine; D000109:Acetylcholine; D004298:Dopamine; D001640:Bicuculline
keywords: GABA; HRV analysis; heart rate variability; intrinsic cardiac properties; sympatho-vagal balance; zebrafish heart