Electrical Excitation of the Heart in a Basal Vertebrate, the European River Lamprey (Lampetra fluviatilis)

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. . Studies on cyclostome hearts may provide insights into the evolution of the vertebrate heart and thereby increase our understanding of cardiac function in higher vertebrates, including mammals. To this end, electrical excitability of the heart in a basal vertebrate, the European river lamprey (Lampetra fluviatilis), was examined. Ion currents of cardiac myocytes, action potentials (APs) of atrial and ventricular muscle, and electrocardiogram (in vivo) were measured using the patch-clamp method, intracellular microelectrodes, and trailing wires, respectively. The characteristic features of fairly high heart rate (28.4 5 3 beats min 21 ) and short AP duration (550 5 44 and 122.1 5 28.5 for ventricle and atrium, respectively) at low ambient temperature (57C) are shared with cold-active teleost fishes. However, the ion current basis of the ventricular AP differs from that of other fishes. For inward currents, sodium current density (I Na ) is lower and calcium current density (I Ca ) higher than in teleost ventricles, while the kinetics of I Na is slow and that of I Ca is fast in comparison. Among the ventricular repolarizing currents, the delayed rectifier K 1 current is smaller than in myocytes of several teleost species. Unlike mammalian hearts, ATPsensitive K 1 channels are constitutively open under normoxic conditions, thus contributing to negative resting membrane potential and repolarization of APs. Upstroke velocity of AP (5.4 5 0.9 and 6.3 5 0.6 V s 21 for ventricular and atrial myocytes, respectively) is slower than in teleost hearts. Excitability of the lamprey heart seems to possess both primitive and advanced characteristics. Short APs are appropriate to support brief and vigorous contractions (in common with higher vertebrates), while relatively low AP upstroke velocities enable only relatively slow propagation of contraction over the heart. The University of Chicago Press

Ion transport in the zebrafish kidney from a human disease angle: possibilities, considerations, and future perspectives

“…In the pursuit to define the electrophysiological characteristics of single or multiple electrolyte channels in cells, Haverinen et al (21) and Chen et al (48) have explored the patchclamp technique. After the isolation of their cell type of interest, ventricular myocytes from Lamprey (Lampetra fluviatilis) and zebrafish brain and liver cells, respectively, these authors successfully recorded the electrical current of the channels.…”

Temperature-dependence of L-type Ca2+ current in ventricular cardiomyocytes of the Alaska blackfish (Dallia pectoralis)

“…ND, Not determined. Species are: Squalus acanthias , spiny dogfish; Danio rerio , zebrafish; Dallia pectoralis , Alaska blackfish; Carassius carassius , crucian carp; Trachemys scripta , red-eared slider turtle; Scomber japonicas , Pacific mackerel; Oncorynchus mykiss , rainbow trout; Thunnus orientalis , Pacific bluefin tuna; Trachemys scripta scripta , yellow-bellied turtle; Varanus exanthematicus , Varanid lizard; Acipenser baerii , Siberian sturgeon; Lampetra fluviatilis , European lamprey; Lota lota , burbot; Perca fluviatilis , European perch. a (Maylie and Morad 1995) b (Brette et al 2008) c Acclimation temperature 21°C (Zhang et al 2011) d (Vornanen and Paajanen 2004) e Carassius carassius : acclimation temperature 17°C; Both Carassius carassius and Oncorynchus mykiss recorded at 22°C (Vornanen 1998) f (Stecyk et al 2007) g (Shiels et al 2004) h Acclimation temperature 14°C, recorded at 19°C (Shiels et al 2014) i (Galli et al 2006) j (Galli et al 2009) k (Haworth et al 2014) l (Haverinen et al 2014) m (Shiels et al 2006) …”

Ionic basis of atrioventricular conduction: ion channel expression and sarcolemmal ion currents of the atrioventricular canal of the rainbow trout (Oncorhynchus mykiss) heart

“…This Communicated by B. Pelster. creates a delay that allows enough time for ventricular filling before the ventricle contracts (Meijler and Janse 1988;Sedmera et al 2003;Milan et al 2006;Haverinen et al 2014;Stoyek et al 2016;Billette and Tadros 2019). Another inherent characteristic of the vertebrate AV tissue is its ability to block AP conduction if the frequency of APs arriving from the atrial myocardium is high (Irisawa 1978;Billette and Tadros 2019).…”