Stimulation of frog (Rana pipiens) sartorius muscle accelerates release of Ca(45), but only during the period of stimulation. No appreciable difference is obtained in the calcium released per impulse whether stimulation is at a rate of 20/sec. or 0.5/sec. However, prior stimulation may appreciably increase the loss per impulse. In unfatigued muscles, the minimum amount of calcium liberated duri...

To determine whether adding blood to a cardioplegic solution affects myocardial preservation, a randomized prospective study was carried out in 60 patients undergoing coronary revascularization to compare the effects of crystalloid potassium cardioplegics (group C) and potassium cardioplegic solutions to which blood has been added (group B) on markers of myocardial metabolism (lactate, inorgani...

We have examined the effects of ryanodine, an inhibitor of the release of sarcoplasmic reticulum calcium in cardiac muscle, on contractile tension and calcium-45 movement in aortic smooth muscle of guinea pigs to learn whether this agent also modifies the release of stored calcium in vascular smooth muscle. Ryanodine (3-100 microM) suppressed the phasic contractions induced by caffeine and nore...

Lactococcin G is a novel lactococcal bacteriocin whose activity depends on the complementary action of two peptides, termed alpha and beta. Peptide synthesis of the alpha and beta peptides yielded biologically active lactococcin G, which was used in mode-of-action studies on sensitive cells of Lactococcus lactis. Approximately equivalent amounts of both peptides were required for optimal bacter...

BK channels modulate neurotransmitter release due to their activation by voltage and Ca(2+). Intracellular Mg(2+) also modulates BK channels in multiple ways with opposite effects on channel function. Previous single-channel studies have shown that Mg(2+) blocks the pore of BK channels in a voltage-dependent manner. We have confirmed this result by studying macroscopic currents of the mslo1 cha...

It is generally considered that both w and i3-adrenoceptors exist in rat parotid glands (1, 2). In our previous paper, the effect of adrenergic stimuli on spontaneous potassium fluxes was found to be distinctly different between at and i3-adrenergic agonists, the former increases potassium efflux and the latter decreases potassium release (3, 4). The present in vitro investigation was undertake...

Enzyme secretion caused by epinephrine in rat parotid slices is accelerated by addition of inosine and adenine to the medium. The purines apparently aid in maintaining the ATP supply. Epinephrine causes a decrease of the intracellular ATP concentration within 1 min after its addition to the slices. Ouabain which inhibits the Na+,K+-activated ATPase, thus conserving ATP, accelerates enzyme secre...

Takahashi, Akira, Eiko Kishi, Hirohisa Ishimaru, Yasushi Ikarashi, and Yuji Maruyama. Stimulation of rat hypothalamus by microdialysis with K1: increase of ACh release elevates plasma glucose. Am. J. Physiol. 275 (Regulatory Integrative Comp. Physiol. 44): R1647–R1653, 1998.— The effects of stimulation of the ventromedial hypothalamus (VMH) or lateral hypothalamus (LH) with potassium chloride t...

This study characterizes the sequential alterations of, and relations between, multiple electrolytes in cytoplasm, mitochondria, and whole cells during hypoxia and on reoxygenation in isolated neonatal rat ventricular myocytes. Subcellular electrolyte content and distribution were measured by electron probe x-ray microanalysis, membrane phospholipid degradation by tritiated arachidonic acid rel...