On the effect of ammonium and lithium ions upon frog nerve deprived of sodium

Edward Trautner (1890-1978), a pioneer of psychopharmacology

This article examines the scientific career of Edward Trautner, who did pioneering research in the 1950s on lithium treatment for psychiatric disorders. Trautner was the first scientist to study the mechanism of action of lithium as a psychiatric medication. His research established that lithium could be used safely and rationally, and anticipated by a decade the large volume of research in the 1960s and 1970s that led to international acceptance of lithium treatment for mood disorders. Trautner was a pioneer of biological psychiatry who considered pharmacology to be a useful therapeutical tool rather than a permanent cure for putative chemical imbalances. His research involved cross-disciplinary collaborations that combined clinical and laboratory research in the disciplines of psychiatry, physiology, biochemistry, teratology, and even oncology. Trautner himself had a multidisciplinary background that included publications in literature and philosophy.

Hyperlithemia correction and persistent delirium

Experience with three patients whose courses are described suggested that delirium and persistent neurologic dysfunction follow rapid correction of hyperlithemia, which develops after regular lithium doses. From all retrievable published reports of adult hospitalization for hyperlithemia, all cases that described cognitive dysfunction after lithium administration for at least 10 days with insubstantial neuroleptic exposure were selected. Lithium was universally discontinued before or on admission. Of the 65 such cases, 50 were at least somewhat responsive on admission; of these, substantial deterioration during hospitalization occurred in 56%. Dialysis was associated with greater incidence of persistent neurologic sequelae (62% vs. 22%, P = .012) and deterioration during hospitalization (85% vs. 46%, P = .016), although cognitive dysfunction on hospital admission was less (P < .001) for patients who were then dialyzed. The greater neurotoxicity after dialysis suggests that while hyperlithemia can be toxic, its rapid correction can be more toxic. Parallels with hyponatremia, including a potential mechanism, suggest that gradual rather than abrupt correction of hyperlithemia might decrease the risk of neurotoxicity.

Lithium entry into neural cells via sodium channels: a morphometric approach

Rat cerebral cortical explants prepared from 18-day-old embryos were grown for 18 days in vitro. Cultures were exposed to Na+, Li+ and choline+ media, respectively, in the presence or absence of tetrodotoxin and/or veratridine, and processed for electron-microscopy. Veratridine (50 microM) induced an increase in summated and mean areas of neuronal profiles in Na+- and Li+-media but not in the choline+-medium: the summated perimeters did not change. The mean value of the neuronal form factor was significantly elevated following exposure to veratridine in a Na+- or Li+-dependent manner, indicating that the shape of the sectioned neuronal elements shifted towards an (ideal) circle. Qualitative assessment revealed an increased electron-lucency of the cytoplasm of neuronal profiles in Na+- and Li+-media containing veratridine. The veratridine-induced neuronal changes were inhibited by simultaneous addition of tetrodotoxin (1 microM) to the media. In the case of the glial cells, the values of the summated area and form factor did not change in the various experimental groups. The area of the extracellular space per unit area of sections significantly decreased in the Na+- and Li+-media following veratridine exposure; this did not occur in the choline+-medium. The results indicate a considerable swelling of the neuronal elements, reflecting cation, Cl- and water uptake following prolonged sodium channel activation in the presence of Na+ or Li+ ions. The quantitative ultrastructural data strongly suggests an entry of Li+ ions into cultured rat cerebral cells via sodium channels.

Ionic interactions in acetylcholine contraction of the denervated rat diaphragm

1. The nature of the drug-receptor interaction in the acetylcholine-induced contraction of the denervated rat diaphragm was studied both by altering the external ionic environment and by determining its drug sensitivity.2. The response to acetylcholine was insensitive to tetrodotoxin or saxitoxin, but was abolished by procaine.3. It was unaffected by levels of MnCl(2) sufficient to block the response of the innervated diaphragm to electrical stimulation, although higher levels reduced the response. The effect of Mn(++) on the innervated diaphragm was overcome by raising the external Ca(++) level; this was ineffective in the denervated preparation.4. In spite of its insensitivity to tetrodotoxin the acetylcholine contraction was reduced and prolonged by low external Na(+) levels. This prolongation was not found when Li(+) substituted for Na(+).5. Increasing the external level of Ca(++) or Mg(++) 3 to 5-fold reduced the acetylcholine contraction; high Ca(++) also prolonged it. Reduction in the divalent cation level was without effect.6. Procaine inhibition of the acetylcholine response was largely competitive, as was inhibition due to (+)-tubocurarine. This was shown by probit analysis and the dose-ratio test.7. Thiocyanate (12 mM) augmented and prolonged the contraction; this action was modified by altering the Ca(++) or Mg(++) level of the solution.8. The acetylcholine receptor resembles that of the innervated postsynaptic membrane.

The effects of saxitoxin and tetrodotoxin on nerve conduction in the presence of lithium ions and of magnesium ions

1. It has been shown that nerve fibres from rat cauda equina will conduct action potentials after immersion in saline in which lithium chloride is substituted for sodium chloride.2. Both saxitoxin and tetrodotoxin inhibit lithium-generated action potentials. The concentration of toxin needed to inhibit the lithium-generated action potentials is similar to that needed to inhibit sodium-generated action potentials.3. If magnesium chloride is added to the saline to give a concentration of 10-15 mM there is usually a slight fall in amplitude of the compound action potential. Saxitoxin and tetrodotoxin now inhibit the action potential to a greater degree than in the absence of magnesium ions.

Salivary excretion of lithium. II. Functional analysis

Salivary Li+ was actively secreted by the cat submaxillary gland, inversely to the rate of flow, at concentrations above serum level. Stop-flow studies indicated ductal secretion of Li+ by a HgCl2 and ouabain-sensitive mechanism. Salivary secretion of Li+ did not resemble Na+ but was similiar to K+ secretion.

Crayfish muscle fiber: ionic requirements for depolarizing synaptic electrogenesis

Presence of sodium in the bathing medium is not essential for the electrically excitable depolarizing electrogenesis of crayfish muscle fibers, production of action potentials being dependent on calcium. The depolarizing electrogenesis of the excitatory synaptic membrane component does require sodium, however, and this ion cannot be replaced by lithium as it can in spike electrogenesis of many cells. Ionophoretic applications of glutamate, which in the presence of sodium depolarize the cell by activating the excitatory synaptic membrane, are without effect in the absence of sodium. Not only is there no depolarization, but the membrane conductance also remains unchanged. Thus, in the absence of inward movement of sodium across the synaptic membrane there is also no outward movement of potassium. Accordingly, it seems that increased conductance for potassium is not an independent process in the synaptic membrane, whereas it is independent of sodium activation in spike electrogenesis. Chloride activation is independent, however; increase in conductance and the electrogenesis of the inhibitory synaptic component are not affected by the absence of sodium. Implications of these findings regarding the structure of differently excitable membrane components are discussed.

The clinical laboratory and electroencephalographic effects of lithium

Eleven patients (six manic, five non-manic) were studied during administration of lithium carbonate. All patients manifested neutrophilia during administration and there was a tendency for elevation in the fasting blood sugar. Serial EEG examinations and lithium determinations were done throughout the study in nine patients. The records of all nine patients showed profound changes in the form of diffuse slowing, widening of the frequency spectrum, potentiation and disorganization of background rhythm. Sensitivity to hyperventilation and paroxysmal bilaterally synchronous delta activity were also noted. Potentiation of an epileptic focus was observed in the EEG of one patient. These findings indicate that the CNS effect of lithium is both cortical and subcortical.

Competition between sodium and calcium ions in transmitter release at mammalian neuromuscular junctions

1. Frequencies of miniature end-plate potentials (m.e.p.p.s) were recorded at neuromuscular junctions in rat diaphragm-phrenic nerve preparations in vitro.2. In the presence of raised [K] (15-20 mM) lowering [Na] caused a rapid increase in m.e.p.p. frequency whether [Ca] was low or normal. Raising [Na] towards the normal concentration (162 mM) caused a slow fall in frequency and raising [Ca] in the range 0.32-2 mM caused a slow increase in frequency. These effects were less in the normal [K] (5 mM).3. Mean m.e.p.p. frequencies were determined for solutions containing 15 mM-K and combinations of [Ca] and [Na]. M.e.p.p. frequency varied inversely with [Na] when [Ca] was constant. In each of the three Na concentrations used (162, 113 and 65 mM) raising [Ca] in the range 0.32-2 mM increased m.e.p.p. frequency but when raised above 2-3 mM, Ca depressed frequency.4. A model was proposed in which Ca affected transmitter release by changing the concentration in the presynaptic membrane of a complex CaX to which the rate of transmitter release was directly proportional. Higher concentrations of Ca depressed transmitter release by inactivating CaX. Sodium ions competitively depressed release either by competing with calcium ions for association with X or by reducing the affinity of X for Ca.5. When [Na] was lowered in solutions containing raised [Mg] and [Ca], the increase of mean m.e.p.p. frequency was greater than that observed in raised [Ca] and normal [Mg] and was of the same order as the increases seen in low [Ca]. The result was interpreted to indicate either that Na and Mg do not compete with Ca at the same site or that Mg affects the affinity of X for Ca and Na.6. The effect of lowering [Na] on m.e.p.p. frequency was a specific effect of Na ions. When LiCl was substituted for NaCl, the increase of m.e.p.p. frequency persisted. Changes in [Cl] had no effect on m.e.p.p. frequency.7. There was a linear relation between the mean logarithm of m.e.p.p. frequencies and [K], the slope of the relation increasing as [Na] was lowered. Conversely, lowering [Na] caused a greater increase in m.e.p.p. frequency as [K] was raised.8. The variation of m.e.p.p. frequencies in a diaphragm was roughly proportional to a second or higher power of [Na] and inversely proportion to [Ca]. It was thought that this could be due to differences in chelation of Ca which were more apparent at low Ca concentrations.9. The similarities between the effects of Na, Ca and K on m.e.p.p. frequency and the effects of these ions on Ca-influx in heart muscle led to the suggestion that transmitter release is proportional to the concentration of a negatively charged complex of a carrier X with one calcium ion (CaX) at the internal surface of the membrane and that changes in membrane potential affect transmitter release by changing the distribution or location of CaX in the membrane.