Effect of GABAergic and adrenergic agents on activity of Na+/K+ pump and Cl−-cotransport in somatic muscle cells of earthworm Lumbricus Terrestris

Abstract

GABA, baclofen, epinephrine, and norepinephrine hyperpolarized the membrane of earthworm somatic cells. This effect was prevented by furosemide, removal of Cl- from the medium, or activation of Na+/K+ pump by 3-fold increase external potassium concentration. It was hypothesized that GABA, baclofen, epinephrine, and norepinephrine stimulate Na+/K+ transport via specific receptor inputs, but their effect on resting potential can be realized only under conditions of working Cl- symport.

Gene Expression Analysis of CL-20-Induced Reversible Neurotoxicity Reveals GABAAReceptors as Potential Targets in the EarthwormEisenia fetida

“…Like GABA, norepinephrine hyperpolarizes the membrane of earthworm somatic cells, possibly by stimulating the Na + /K + pump via α-adrenergic receptors (48;49). In conjunction with the up-regulation of GABA A -R, the up-regulation of DBH was probably a concerted action to counter the blocking of the GABA A -R chloride ionophore by CL-20 that reduced GABAergic inhibition (30).…”

“…Like GABA, norepinephrine hyperpolarizes the membrane of earthworm somatic cells, possibly by stimulating the Na + /K + pump via α-adrenergic receptors. 48,49 High interindividual variability in expression may be due to individual differences in the toxicokinetics of CL-20, variability in individual expression in this gene, or unknown regulatory mechanisms.…”

“…Although statistically insignificant due to high inter-individual variation of expression, effects of CL-20 on the transcript encoding DBH (an enzyme converting dopamine to norepinephrine) suggest potential impacts of CL-20 on the adrenergic system, which remains to be confirmed (Table and Figure ). Like GABA, norepinephrine hyperpolarizes the membrane of earthworm somatic cells, possibly by stimulating the Na + /K + pump via α-adrenergic receptors. , High inter-individual variability in expression may be due to individual differences in the toxicokinetics of CL-20, variability in individual expression in this gene, or unknown regulatory mechanisms.…”