Modulation of the respiratory rhythm by gap-junction blockers 18-α-glycyrrhetinic acid and 18-β-glycyrrhetinic acid.
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Date
2013-07
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Abstract
Gap junction proteins are expressed in the pre-Bötzinger complex
of the respiratory network but it remains under discussion how they
modulate the respiratory rhythm generation. In the present study we
tested whether the gap junction blockers 18-β-glycyrrhetinic acid (18-β-
GA) and 18-α-glycyrrhetinic acid (18-α-GA) change either the phrenic nerve
(PN) discharge frequency or amplitude. The PN discharge was recorded
using the working heart-brainstem preparation of adult wistar rats (P22-
P28) exposed to increasing concentrations of the gap junction blockers (0.1;
1; 10; 20 μM). With the two lower concentrations (0.1; 1 μM) of 18-β-GA,
PN discharge frequency decreased to 46±15% (p=0.007) of the control value
while it increased to 173±57% (p=0.16) with the two higher concentrations
(10; 20 μM). Surprisingly, with 18-α-GA the PN discharge frequency was
not significantly changed with any of the concentrations used. Enhancing
the respiratory drive with 12% CO2, the PN discharge frequency increased
tendencially with rising concentrations of 18-β-GA, but again no significant
change was observed with 18-α-GA. PN-amplitudes were slightly reduced
over the course of the experiments, while the frequency of the heartbeat
was not significantly changed at any time with any concentration.
Description
Keywords
gap junctions, gap junction blockers, respiratory rhythm generation, working heart brainstem preparation, 18-α-glycyrrhetinic acid, 18-α-glycyrrhetinic acid
Citation
Juntermanns Benjamin, Göpelt Kirsten, Büsselberg Dietrich. Modulation of the respiratory rhythm by gap-junction blockers 18-α-glycyrrhetinic acid and 18-β-glycyrrhetinic acid. Indian Journal of Physiology and Pharmacology. 2013 Jul-Sept; 57(3): 214-224.