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Forschungsdatenbank PMU-SQQUID

Putative role of epithelial sodium channels (ENaC) in the afferent limb of cardio renal reflexes in rats.
Ditting, T; Linz, P; Hilgers, KF; Jung, O; Geiger, H; Veelken, R;
Basic Res Cardiol. 2003; 98(6): 388-400.
Originalarbeiten (Zeitschrift)


Ditting Tilmann
Veelken Roland


Recent studies suggest a role of ion channels of the DEG/ENaC family for mechanosensation in different species and in baroreceptor reflex control in rats. We tested the hypothesis that ENaC within the cardiac sensory network are mandatory for mechanosensation. Experiments were performed in male Sprague-Dawley rats, isolated nodose ganglion cells with cardiac afferents and isolated vagus nerves. Epicardial delivery of the amiloride analogue benzamil intended to specifically inhibit ENaC presumably located on cardiac sensory afferents indeed blunted the mechanosensitive (i. e., sympathoinhibition by intravenous volume loading [-32% and -42% in treated groups vs. -67% in controls; n = 7 each; p < 0.05]) as well as-though to a lesser extent-the 5-HT(3)-mediated chemosensitive cardiorenal reflex in vivo in a dose-dependent manner. Using patch clamp technique, however, it turned out that neither amiloride nor benzamil influenced mechanically induced currents in ganglion nodosum cells in vitro, stimulated by hypoosmotic stress. The unspecific stretch activated ion channel blocker gadolinium completely abolished mechanically induced currents, indicating respective cells were mechanosensitive. In isolated vagus nerves benzamil impaired action potentials obtained by electrical stimulation (C-spike amplitude [-33%]; latency [+12%]; n = 8; p < 0.05). Our findings at least cast doubt on ENaC exclusively playing a specific role as mechanotransducers within the cardiac sensory network. Other ion channels might be involved. Furthermore the observed findings in vivo could also be due to unspecific disturbance of afferent signal conduction.

Useful keywords (using NLM MeSH Indexing)

Action Potentials/drug effects






Blood Pressure/physiology

Cells, Cultured

Dose-Response Relationship, Drug

Electrophysiologic Techniques, Cardiac


Heart/drug effects



In Vitro Techniques

Kidney/drug effects



Nodose Ganglion/cytology

Patch-Clamp Techniques


Rats, Sprague-Dawley

Sodium Channels/metabolism*

Vagus Nerve/drug effects

Vagus Nerve/physiology

Find related publications in this database (Keywords)

cardiac sensory afferents
mechanosensitive ion channel
conduction velocity