Endogenous sodium pump inhibitors, diabetes mellitus and preeclampsia Preliminary observations and a hypothesis.

Endogenous inhibitors of the Na/K-ATPase (NKA) and diabetes mellitus (DM) are both risk factors for preeclampsia and NaCl sensitive hypertension. Our goal was to test the hypothesis that NaCl supplementation, induces preeclampsia-like symptoms in pregnant rats with DM via stimulation of marinobufagenin (MBG), a natriuretic and vasoconstrictor inhibitor of the NKA. Type 2 DM in female Sprague-Dawley rats was induced by administration of 65mg/kg streptozotocin at day 4 post-partum.

Endogenous bufadienolide mediates pressor response to ethanol withdrawal in rats.

An endogenous natriuretic and vasoconstrictor Na/K-ATPase inhibitor, marinobufagenin (MBG), is implicated in NaCl-induced hypertension and in ethanol addiction. In rats, MBG suppresses voluntary alcohol intake, while immunization against MBG induces alcohol-seeking behavior. Since alcohol withdrawal is associated with elevation of blood pressure (BP) and renal sodium retention, we hypothesized that MBG mediates pressor response to ethanol withdrawal.

Endogenous digitalis-like ligands and Na/K-ATPase inhibition in experimental diabetes mellitus.

Dysregulation of the Na/K-ATPase (NKA) in the kidney, cardiovascular system, and peripheral nervous system is believed to contribute to pathogenesis of diabetes mellitus (DM) and its complications. Recently we demonstrated that, in addition to endogenous ouabain (EO), mammalian tissues contain another NKA inhibitor, a bufadienolide marinobufagenin (MBG). In vitro MBG, a natriuretic and a vasoconstrictor, acts as a selective inhibitor of alpha-1 NKA, the main isoform of the sodium pump in renal tubules and vascular smooth muscle.

Marinobufagenin (MBG) suppression of ethanol-seeking behavior is associated with inhibition of brain cortex Na/K-ATPase in mice.

In the present study the hypothesis was tested that sodium pump ligands (SPL) can modulate alcohol-seeking behavior and that this effect is related to changes in Na/K-ATPase activity in the central nervous system. Mice were tested for initiation of ethanol intravenous self-administration (IVSA) following i.p.

Endogenous digitalis-like ligands of the sodium pump: possible involvement in mood control and ethanol addiction.

This review addresses possible involvement of endogenous digitalis-like sodium pump ligands (SPL) in the mood control and ethanol addiction. Endogenous SPL include cardenolide and bufadienolide classes. Multiple SPL and multiple isoforms of the Na/K-ATPase, one of the key membrane enzymes, comprise a complex regulatory system.

Involvement of endogenous digitalis-like factors in voluntary selection of alcohol by rats.

This study tested the hypothesis that endogenous digitalis-like factor (DLF) is involved in the development of alcohol dependence in rats. In 33 male Wistar rats in conditioned place preference (CPP) experiment, ethanol evoked increase in time spent in the ethanol-associated compartment (702+/-82 in ethanol-treated vs. 426+/-86 sec in the controls).