Lithium reduces the number of acetylcholine receptors in skeletal muscle

Lithium causes differential effects on postsynaptic stability in normal and denervated neuromuscular synapses

Lithium chloride has been widely used as a therapeutic mood stabilizer. Although cumulative evidence suggests that lithium plays modulatory effects on postsynaptic receptors, the underlying mechanism by which lithium regulates synaptic transmission has not been fully elucidated. In this work, by using the advantageous neuromuscular synapse, we evaluated the effect of lithium on the stability of postsynaptic nicotinic acetylcholine receptors (nAChRs) in vivo. We found that in normally innervated neuromuscular synapses, lithium chloride significantly decreased the turnover of nAChRs by reducing their internalization. A similar response was observed in CHO-K1/A5 cells expressing the adult muscle-type nAChRs. Strikingly, in denervated neuromuscular synapses, lithium led to enhanced nAChR turnover and density by increasing the incorporation of new nAChRs. Lithium also potentiated the formation of unstable nAChR clusters in non-synaptic regions of denervated muscle fibres. We found that denervation-dependent re-expression of the foetal nAChR γ-subunit was not altered by lithium. However, while denervation inhibits the distribution of β-catenin within endplates, lithium-treated fibres retain β-catenin staining in specific foci of the synaptic region. Collectively, our data reveal that lithium treatment differentially affects the stability of postsynaptic receptors in normal and denervated neuromuscular synapses in vivo, thus providing novel insights into the regulatory effects of lithium on synaptic organization and extending its potential therapeutic use in conditions affecting the peripheral nervous system.

Drugs That Induce or Cause Deterioration of Myasthenia Gravis: An Update

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder which is characterized by presence of antibodies against acetylcholine receptors (AChRs) or other proteins of the postsynaptic membrane resulting in damage to postsynaptic membrane, decreased number of AChRs or blocking of the receptors by autoantibodies. A number of drugs such as immune checkpoint inhibitors, penicillamine, tyrosine kinase inhibitors and interferons may induce de novo MG by altering the immune homeostasis mechanisms which prevent emergence of autoimmune diseases such as MG. Other drugs, especially certain antibiotics, antiarrhythmics, anesthetics and neuromuscular blockers, have deleterious effects on neuromuscular transmission, resulting in increased weakness in MG or MG-like symptoms in patients who do not have MG, with the latter usually being under medical circumstances such as kidney failure. This review summarizes the drugs which can cause de novo MG, MG exacerbation or MG-like symptoms in nonmyasthenic patients.

Ophthalmic adverse effects of lithium

Lithium is the current mainstay treatment for both acute and maintenance management of bipolar disorders. However, its narrow therapeutic index and array of side effects, although well-documented, can be challenging to manage. Comparatively, the side effects of lithium that involve the ophthalmic structures are not as well established in the literature and only partially appreciated, which can potentially lead to noncompliance. In this article, an extensive literature review of lithium and its ophthalmic adverse effects were performed and comprehensively summarized. Based on the search, documented ophthalmic adverse effects of lithium include: exophthalmos; abnormal eye movements; ocular myasthenia gravis; papilledema; photophobia; and abnormal tear film, contributing to dry eye disease. Additional studies are anticipated to be helpful in expanding the current understanding of lithium and its adverse ophthalmic side effects and certainly warranted to fill the knowledge gap. Close interprofessional management between psychiatrists and ophthalmologists is expected to be beneficial in patient care.

Opioid peptides and receptors in relation to affective illness. Effects of desipramine and lithium on opioid receptors in rat brain

A brief review is given of clinical and experimental evidence supporting the notion that opioid peptides and opioid receptors play a role for the regulation of mood and activity, and that they could be involved in the pathophysiology of affective illness and the action of antimanic and antidepressant treatment modalities. We have carried out in vitro and in vivo studies on the effects of desipramine and lithium on opioid receptors in rat brain. In vitro desipramine inhibited the binding of 3H-enkephalinamide to neuronal membranes (P2-fractions) through mechanisms not yet known. Treatment with desipramine in vivo (10 mg/kg body weight/day) caused a down-regulation of 3H-enkephalinamide binding in the basal ganglia and the hippocampus, while no effects could be observed in the cerebral cortex and the rest of the forebrain. In vitro addition of lithium inhibited enkephalin binding to opioid receptors through a reduction in the number of binding sites, while the affinity remained unchanged or was changed only slightly. Treatment with lithium in vivo for three weeks with lithium doses providing serum lithium concentrations of about 1 mM also caused a down-regulation in the number of opioid binding sites in the cerebral cortex, the hippocampus, and the basal ganglia, while no changes could be observed in affinity. The studies suggest that desipramine and lithium, both effective in the treatment of manic-depressive illness, may share certain actions on opioid receptors in the brain.

Exocytotic "constipation" is a mechanism of tubulin/lysosomal interaction in colchicine myopathy

Colchicine, a known microtubule disrupting agent, produces a human myopathy, characterized by accumulation of lysosomes. We have created a reliable animal model of colchicine myopathy that replicates the subacute myopathy seen in humans, reproducing the chronic proximal weakness and vacuolar changes in nonnecrotic myofibers. If a microtubule network plays a role in lysosomal function in muscle, disturbance of it could alter degradation of intrinsic membrane receptors, presumably at some intracellular processing site or at exocytosis. Thus, we examined, as a possible cellular pathogenesis of colchicine myopathy, how the muscle cytoskeleton affects the degradation of membrane proteins, which are processed through the endosomal/lysosomal pathway. We used the acetylcholine receptor as a model membrane component in cultured myotubes allowed to preincubate with colchicine. We tested at which step colchicine interferes with receptor trafficking by accounting for internalization, delivery to lysosomes, hydrolysis, or exocytotic release of debris. We report that colchicine significantly decreases the exocytosis of AChRs but does not affect receptor internalization, lysosomal hydrolysis, or the number of surface membrane receptors. Further, our immunofluorescence observations revealed a morphologic tubulin network in rat skeletal muscle that is more densely distributed in white (mitochondria-poor) muscle fibers than in red (mitochondria-rich) fibers but is present in both. Ultrastructurally, immunogold labeling localized tubulin in the intermyofibrillar region in a long and linear fashion, unassociated with myofibers or mitochondria. Taken together, our findings suggest the following: (1) Microtubules likely play a functional role in the pathway of lysosomal degradation in normal adult skeletal muscle; (2) The observed decrease in overall apparent degradation of membrane receptors by colchicine must be due primarily to inhibition of exocytosis. These data indicate that lysosomal "constipation" underlies colchicine myopathy. (3) An animal model faithful to the human disorder will allow further pathogenetic studies.

Lithium inhibits the development of physical dependence to clonidine in mice

Based on our previous finding that chronic lithium treatment reduced naloxone-precipitated withdrawal syndrome in morphine-treated mice, the effect of chronic lithium treatment was evaluated on the development of dependence to clonidine. Dependence was induced by injection of either morphine (50, 50 and 75 mg/kg, intraperitoneally with 3 hr interval for 3 consecutive days), or clonidine (2 mg/kg/day, intraperitoneally for 10 days). Naloxone (4 mg/kg, intraperitoneally) precipitated withdrawal signs in both morphine- and clonidine-treated mice. Yohimbine (5 mg/kg, intraperitoneally) precipitated withdrawal signs in the clonidine-treated mice, similar to morphine withdrawal signs; but failed to precipitate any significant sign in the morphine-treated mice. Coadministration of lithium was carried out by adding lithium chloride to drinking water (600 mg/l for 20 days; 10 days before the beginning of clonidine administration and 17 days before the administration of morphine to allow the lithium concentration to reach steady-state). The results indicated that chronic lithium administration significantly attenuated the withdrawal signs, precipitated either by yohimbine or naloxone, in clonidine-treated mice. As a conclusion, clonidine withdrawal signs are very similar to opioid withdrawal signs, and lithium is able to prevent the development of physical dependence to clonidine.

Imipramine binding in depressive patients diagnosed according to different criteria

3H-imipramine binding to platelet membranes, Bmax and KD, was measured in depressed patients, who were divided into endogenous and non-endogenous depression according to three different criteria, the ICD-9, the Newcastle I and the Newcastle II rating scales. Two groups served as controls, a group of healthy volunteers and a group of psychiatric patients suffering from schizophrenia or senile dementia. No significant differences were found in either Bmax or in KD among the different groups of patients and the control groups.

Amitriptyline-induced supersensitivity of a central muscarinic mechanism: lithium blocks amitriptyline-induced supersensitivity

Chronic treatment with amitriptyline produces dose-dependent super-sensitivity of a central muscarinic cholinergic mechanism involved in the regulation of core body temperature. The authors demonstrated that chronic treatment with lithium prevents the induction of this response. The potential clinical and theoretical significance of this finding is set forth.

Inhibition of methyltransferase reduces the turnover of acetylcholine receptors

Because of the putative rule of phospholipid methyltransferase reactions in many important membrane and receptor translocation processes, we studied the effect of methyltransferase inhibitors on acetylcholine receptor (AcChoR) turnover in cultured rat skeletal muscle. Inhibition of methyltransferase significantly reduced the normal rate of degradation of AcChoRs, a process that involves endocytosis. Further, under conditions that greatly accelerate the rate of degradation of AcChoRs--i.e., by addition of anti-AcChoR antibody--methyltransferase inhibitors again significantly reduced receptor turnover. AcChoR synthesis was unaffected. Thus, the net effect of this treatment was slowing of the antibody-induced loss of surface AcChoRs. That this drug effect was mediated specifically by inhibition of methylation reactions was suggested by certain additional pharmacologic features: partial reversibility of the effect by methionine, enhancement by homocysteine, and correspondence with marked inhibition of phospholipid methylation. The substrate specificity of the methyltransferase inhibitors capable of reducing AcChoR degradation suggests that phospholipid methylation reactions may be most relevant. Methyltransferase inhibitor drugs may provide a therapeutic strategy in receptor disorders such as myasthenia gravis, in which accelerated receptor endocytosis plays a major role.

Temperature as a dependent variable in the study of cholinergic mechanisms

1. Change in core temperature over time can be used as a dependent variable when studying the effects of manipulations on neurotransmitter systems. This article focuses on the measurement of core temperature as a strategy for detecting changes in the status of cholinergic systems. 2. Cholinergic neurons participate in the process of thermoregulation and interventions affecting them alter the thermal response to cholinomimetics. For example, chronic treatment with amitriptyline, chronic swim stress and inescapable footshock supersensitize rats to the hypothermic effects of oxotremorine. 3. This is consistent with the hypothesis that the pathophysiologies of tricyclic antidepressant withdrawal phenomena and stress involve supersensitivity of muscarinic mechanisms. 4. Uses of thermoregulation paradigms for investigating the actions of lithium ion, electroconvulsive shock and substances of abuse on muscarinic mechanisms are discussed. Applications to problems in the arena of clinical research are highlighted.

A review of the biochemical and neuropharmacological actions of lithium

The pharmacological actions central to the therapeutic effects of lithium have not yet been established, despite almost 40 years of clinical use and scientific investigation. We review the biochemical and neuropharmacological data relating to this problem and attempt to identify profitable areas for further research.

Mechanism of action of lithium on acetylcholine receptor metabolism in skeletal muscle

Changes in the levels of cations within skeletal muscle are thought to mediate the neural regulation of turnover of extrajunctional acetylcholine receptors (AChRs). We have used lithium as a probe of these cation influences because of its resemblance to calcium and other ions. In the present experiments we studied the mechanism of action of lithium on AChR metabolism in cultured mammalian skeletal muscle. We measured the effects of lithium on AChR turnover (using [125I]alpha-bungarotoxin binding), and evaluated the resemblance of lithium and calcium in producing their effects on AChR metabolism. Our results provide insight into the mechanisms of action of lithium and the cellular processes controlling AChR metabolism in muscle. Lithium reduces the number of AChRs in skeletal muscle in vitro to a degree similar to that which we previously reported in vivo. Lithium appears to enter cells via both sodium and calcium channels. It then produces its effect on levels of AChRs primarily by selectively reducing AChR synthesis and insertion into the surface membrane. Lithium induces this change in AChR metabolism in a manner resembling neural and calcium-mediated effects on AChRs. Phosphoinositide pathways may be involved in the lithium-induced effects. Further analysis of the effects of lithium on AChR turnover should provide new information about the mechanisms underlying the cellular control of receptor metabolism.

Cholinergic mechanisms in affective disorders. Future directions for investigation

Advances in clinical and basic research methodology combined with clearly articulated concepts create new opportunities for researching the roles of cholinergic mechanisms in the pathophysiology of affective disorders. Areas for study include: roles of cholinergic mechanisms in mediating effects of stress and cholinergic mechanisms linking the pathophysiologies of affective and panic disorders, use of pharmacologic agents to produce cholinergic system supersensitivity in modeling biologic aspects of affective illness, use of multigenerational intrapedigree studies of cholinergic markers associated with affective disease, research into the neurobiology of lithium and ECT as they pertain to muscarinic cholinergic mechanisms, study of the interrelationship of sodium, calcium and lithium ion metabolism and their relationship to cholinergic-monoaminergic interaction, the development of brain imaging strategies and techniques, e.g., positron emission tomography (PET), to measure changes in cholinergic receptor density and affinity as a function of clinical state, identification and validation of a peripheral model of the central muscarinic receptor, study of the pharmacology of abusable substances and its relationship to mechanisms regulating mood, affect, psychomotor function and other variables related to the affective disorders, and development of in vitro and in vivo models useful in studying the physiology and biochemistry of the interaction of cholinergic and monoaminergic neurons. These models may allow us to bridge the traditional cholinergic and monoamine hypotheses of affective disorders.

Covariation of depressive symptoms, parkinsonism, and post-dexamethasone plasma cortisol levels in a bipolar patient: simultaneous response to ECT and lithium carbonate

A patient presented with concurrent mood congruent delusions, parkinsonism, and elevated post-dexamethasone plasma cortisol levels. This triad could result from simultaneous development of cholinergic-monoaminergic dysfunction within critical limbic and extrapyramidal loci. The magnitude of each abnormality decreased in concert during a course of electroconvulsive therapy (ECT). Remaining abnormalities disappeared during treatment with lithium. Actions of ECT and lithium on muscarinic systems are reviewed, and a strategy for testing the hypothesis that dysfunction of cholinergic-monoaminergic mechanisms develops in parallel in different neural networks is considered.

Pathophysiology of "cholinoceptor supersensitivity" in affective disorders

Phenomenological and physiological variables demonstrate supersensitive changes to cholinergic challenge in affective disorder subjects. Theorists generally assume the primary defect is the postsynaptic muscarinic receptor. However, in addition to defectiveness or up-regulation of this receptor, the appearance of postsynaptic "cholinoceptor supersensitivity" can result from abnormal presynaptic mechanisms, membrane "pathology," derangement of intrasystolic mechanisms that amplify effects of receptor-agonist coupling, or aberrant cholinergic-monoaminergic interaction. This article discusses abnormalities of the postsynaptic receptor, regulation of postsynaptic receptor density, the presynaptic muscarinic receptor, and other mechanisms regulating the release of acetylcholine, membrane dynamics, and "cascade" mechanisms-specifically the phosphatidylinositol (PI) cycle, Ca2+ mobilization, and cyclic guanosine monophosphate (GMP) generation-as causes of cholinergic system "supersensitivity." It is suggested that an approach to the topic emphasizing site of abnormality will encourage greater clarity of thought in the study of the cholinergic component of the pathophysiology of affective illness.

Lithium mechanisms in bipolar illness and altered intracellular calcium functions

Calcium functions as an intracellular second messenger, transducing a variety of hormonal, electrical, and mechanical stimuli by activating a wide range of enzymes. There is evidence, ranging from definitive to strongly presumptive in quality, that lithium can alter many calcium-dependent processes. The list of enzyme systems dependent on calcium and altered by lithium includes adenylate cyclase, glycogen synthase, inositol-1-phosphatase, and calcium adenosine triphosphatase (ATPase). Lithium also interferes with calcium regulation of receptor sensitivity, parathyroid hormone release, microtubule structure, and other systems. All of the neural mechanisms that are hypothesized to explain various psychopharmacological treatments of bipolar illness involve functions that are critically controlled by calcium. Moreover, in every instance, a known action of lithium on calcium function could account for lithium's therapeutic or prophylactic results. From these considerations the dual hypotheses emerge that bipolar illnesses arise from disorders in calcium-regulated functions and that lithium acts by reversing or counterbalancing the effects of these calcium dysfunctions.

Interactions of drugs and electroshock treatment on cerebral monoaminergic systems

The interaction of EST and drugs on the CSF levels of several monoamine metabolites was studied with four drugs that have been used in the treatment of psychiatric disorders, namely, lithium, carbamazepine, imipramine, and haloperidol. EST-drug interactions were observed with each of these drugs on one or more monoaminergic systems. All interactions were antagonistic in nature. Changes in the CSF levels of monoamine metabolites did not always reflect corresponding changes in the monoamine turnover; the increase in 5HIAA seen after chronic Li was due to slower removal of this metabolite from the CSF. However, the changes in the CSF levels of DA and 5HT metabolites following chronic HLDL reflected changes in the turnover of the parent amine in the brain. The effects of both HLDL and EST on DA metabolism in the intact brain could be related to alterations by these treatments of the responsiveness of DA presynaptic receptors. Similarly, the effect of HLDL on 5HT turnover and the antagonistic interaction of EST on this HLDL-induced effect were associated with changes in 3H-IMI binding sites that label the 5HT transporter in serotonergic presynaptic terminals. The results are discussed with the aid of a model that depicts possible relationships between pre- and postsynaptic variables and their influence on each other. According to this model an increase in the neurotransmitter turnover is associated with "down regulation" of both pre- and postsynaptic receptors whereas a decrease in turnover is associated with receptor "up regulation." However, "up regulation" of receptors is not necessarily associated with augmented postsynaptic response. Analysis of the model variables by the "binding equation" which obeys the Clark occupancy principle revealed that receptor "up regulation" which is associated with decreased turnover may result in either an augmented or a depressed postsynaptic response (related to the number of occupied receptors). The direction of the response depends on the ratio between the rate of receptor "up regulation" and the rate of decrease in neurotransmitter turnover.

Effect of chronic lithium on cholinergically mediated responses and [3H]QNB binding in rat brain

Lithium (Li) has been previously reported to increase acetylcholine turnover and release in rat brain and to potentiate the neurotoxicity of cholinergic agents. We studied the effect of chronic Li administration, alone and in combination with the muscarinic antagonist, scopolamine, on two cholinergically-mediated responses and on muscarinic cholinergic receptor (MCR) binding in rat brain. Administered separately, Li and scopolamine enhanced the cataleptic and hypothermic responses to pilocarpine; combined administration resulted in an additive effect on both these measures. [3H]Quinuclidinyl benzilate ([3H]QNB) binding was increased by Li in the corpus striatum but not in the cortex, hippocampus and hypothalamus. Scopolamine increased [3H]QNB binding in the striatum, cortex and hippocampus; Li and scopolamine effects on striatal MCR were not additive. Contrary to a previous report, antagonist-induced MCR supersensitivity was not prevented by concurrent Li administration in any of the brain areas studied. The additive effect of Li and scopolamine on pilocarpine-induced catalepsy and a trend in this direction for pilocarpine-induced hypothermia suggest that the actions of the two agents to enhance cholinergically mediated responses may be achieved by different mechanisms. Supersensitive responses following scopolamine may be attributed to antagonist-induced up-regulation of postsynaptic muscarinic receptors as demonstrated in the binding studies. The effects of Li to enhance cholinergically-mediated catalepsy and hypothermia are interpreted as extending previous reports that Li stimulates brain cholinergic function by a presynaptic increase in acetylcholine turnover and release.

Attenuation by electroshock treatment of the haloperidol-induced rise in the binding of 3H-imipramine to rat brain membranes

Studies were conducted in rats to investigate whether chronic haloperidol treatment, electroshock treatment (EST), or a combination of both affects the high-affinity binding of 3H-imipramine to cerebral membranes. Chronic haloperidol (2 mg/kg SC daily for 28 days) resulted in a significant decrease in the density of binding sites in animals killed 1 h after the last treatment, but binding was markedly enhanced after a "washout" period of 5 days. In animals subjected to EST (20-30 mA, 1.5 s, 60 Hz; three times a week for 4 weeks) and killed 1 h after the last treatment, there were no apparent changes, but when animals were allowed a recovery period of 5 days there appeared to be a slight increase in binding. The marked increase in binding seen after haloperidol withdrawal was no longer apparent in animals treated with both haloperidol and EST, indicating that EST acts to attenuate the increase in binding seen after withdrawal of chronic haloperidol. It is suggested that chronic haloperidol may influence presynaptic recognition sites that regulate serotonin uptake and that EST may interact with haloperidol to "stabilize" these presynaptic sites.

Studies on the role of brain cholinergic systems in the therapeutic mechanisms and adverse effects of ECT and lithium

Brain cholinergic systems are thought to play an important role in memory function and mood regulation. Electroconvulsive therapy (ECT) and lithium (Li) have substantial therapeutic effects on abnormal mood and may adversely affect cognitive processes. The effects of chronic electroconvulsive shock (ECS) and Li administration on brain muscarinic cholinergic receptors (MCR), and on functional correlates of altered brain cholinergic activity, were therefore studied. ECS reduced MCR number in the cerebral cortex and diminished cataleptic responses to the muscarinic agonist, pilocarpine. MCR down-regulation may have therapeutic implications in depression which has been putatively linked to central cholinergic supersensitivity. Alternatively, ECS effects on brain cholinergic function may be involved in the pathogenesis of ECT-induced memory deficits. Both ECS-induced MCR subsensitivity and a clinically equivalent model of ECT-induced anterograde amnesia were not demonstrable after a single ECS, were cumulatively induced by repeated treatments, and may be reversible by administration concurrently with ECS of a muscarinic antagonist. Li increased MCR binding marginally in the cortex and hippocampus and significantly in the corpus striatum. Li substantially enhanced cataleptic and hypothermic responses to pilocarpine. Combined Li-scopolamine pretreatment had an additive effect on these cholinergically mediated responses. Effects of Li and scopolamine on MCR binding were not additive, a finding supporting the conclusion that Li enhances brain cholinergic function by its presynaptic effects on acetylcholine turnover and release. Possible implications for the therapeutic mechanisms and adverse effects of Li are considered.

Antidepressant withdrawal-induced activation (hypomania and mania): mechanism and theoretical significance

Electrocortical and behavioral arousal are separate phenomena subserved by different neural substrata operating in parallel. A comprehensive theory of 'activation' must take into account the relationships between the electrical and behavioral activating systems. In pathological or experimentally induced states paradoxes, resolvable by a theory positing functional interaction between these systems, arise. EEG arousal is directly mediated, in both the waking and sleeping state, by cholinergic mechanisms. Antidepressant withdrawal precipitates cholinergic overdrive; this would account for the apparent disturbances of REM sleep occurring when antidepressants are stopped. Generally, cholinergic overdrive would produce behavioral inhibition but in particular instances it triggers marked psychomotor arousal by mobilizing a 'limbic activating system'. The existence of a monoaminergic 'limbic activating system', system 'A', with the properties attributed to it in this paper, is supported by both clinical and laboratory observations. System 'A' theory provides a parsimonious means of adequately explaining many phenomena. This theory also has in its favor explanatory power and scope. The Cholinergic-Monoaminergic Interaction Theory of antidepressant withdrawal induced activation and of rapidly-cycling manic-depressive illness maintains that system 'A' and a cholinergic inhibitory system interact dynamically, and that excessive monoaminergic function can precipitate excessive cholinergic function and a dearth of monoaminergic function (due to autoregulation) and hence depression. Likewise, excessive cholinergic function is posited to activate monoaminergic systems and hence to secondarily cause behavioral activation. Rapidly-cycling manic-depressive patients, according to the model, develop alternating cholinergic and monoaminergic overdrive states because the homeostatic mechanisms which should serve to maintain, within normal limits, the composite of cholinergic inhibitory and monoaminergic activating influences are defective. Consequently, rather than reaching a reasonable balance compatible with adaptive function there is oscillation between extremes. Each oscillatory movement is actually a move towards the 'golden mean' and is induced by deviation from this ideal but the defective homeostatic mechanisms promote ' perpetual ' overshooting. Lithium and ECT may be useful in the treatment of rapidly-cycling patients as both treatments may down-regulate muscarinic receptors, and otherwise modify cholinergic and monoaminergic systems in ways promoting homeostasis.(ABSTRACT TRUNCATED AT 400 WORDS)

Lithium, red blood cell choline and clinical state. A prospective study in manic-depressive patients

Red blood cell (RBC) choline and ergothioneine levels were measured after repeated sampling of bipolar manic-depressive patients over 11 months of lithium maintenance. In addition, blood levels were measured in healthy volunteers, newly hospitalised lithium-free patients and from patients prior to, and after, initiating lithium. RBC choline levels did not differ between normal volunteers and newly admitted lithium-free patients with either mania or depression. After 4 weeks of lithium treatment RBC choline levels increased 6-fold, whereas the levels of the closely related compound ergothioneine did not change. Significant changes in mood during lithium maintenance were not accompanied by changes in RBC choline levels. These data indicate that lithium produced a specific accumulation of choline in erythrocytes. However the increased levels appear to be unrelated to clinical state and do not distinguish lithium responders from non-responders

Lithium, sodium and potassium transport in erythrocytes of manic-depressive patients

Different Li, Na and K transport pathways were assessed in erythrocytes from manic-depressive patients. No alteration in the Li-Na countertransport, Na,K cotransport or passive permeabilities was observed in either unipolar or bipolar manic-depressive patients. In addition, acute or chronic lithium treatment did not alter the maximal velocity of either the Li-Na countertransport or the Na,K cotransport. A two-fold reduction of the ouabain-sensitive Na efflux was observed among manic-depressive patients without alteration in the affinity of the Na pump for internal Na.

Adrenergic-cholinergic balance and the treatment of affective disorders

Centrally acting cholinomimetic drugs cause anergia, behavioral inhibition and depression. Centrally acting cholinomimetic drugs have antimanic properties. Combinations of acetylcholine precursors and centrally active cholinomimetic agents may cause augmented muscarinic effects, as may a combination of an antiadrenergic and cholinomimetic drugs. Centrally active anticholinergic agents may exert antidepressant effects. Affective disorder patients may show hyperreactivity to cholinomimetic agents, a phenomena which may have diagnostic significance.

Trends in research and treatment of affective disorders

Trends in research on affective disorders were reviewed. Studies which described the contribution of neurotransmitters and neuroendocrines to depression, unipolar and bipolar, and manic states were cited. Women more frequently suffer from affective disorders but women's response to different therapies sometimes is more favorable than men's. Age and married status influence sex differences in the incidence of affective disorders. Symptoms of pain and depression intertwine, and response to analgesia may emerge as an index of response to therapy for depression. Trends in pharmacotherapies for affective disorders were reviewed: lithium, tricyclic antidepressants, and MAOI drugs, as well as trends in the employment of ECT and sleep deprivation to relieve symptoms of affective disorders were reviewed.

Treatment of the "on-off" phenomenon in Parkinsonism with lithium carbonate

Six patients with severe parkinsonism complicated by the "on-off" phenomenon were treated with lithium carbonate in addition to regular antiparkinson medications. A randomized double-blind crossover trial of lithium versus placebo was conducted, followed by an open trial of lithium therapy. Five patients had markedly reductions in akinesia (mean, 70%) and improved by one grade in Parkinson staging. This result was more striking in male than in female patients, and in all responders benefit has been maintained during the open phase of lithium treatment (mean follow-up of 36 weeks). In no patient was a reduction in akinesia observed during placebo treatment. Lithium carbonate appears to offer a new and potentially effective approach to treatment of the on-off phenomenon.

Cell kinetics of lithium-induced granulopoiesis

Lithium has been shown to be an effective inducer of granulopoiesis. The mechanism of lithium action has been shown to influence CFU-s and CFU-c proliferation, increase colony-stimulating factor (CSF) production and reduce erythropoiesis. We report here evidence to show that lithium recruits CFU-c that are not normally in the cell cycle into active DNA synthesis, as measured by hydroxyurea and tritiated thymidine suicide techniques. Furthermore, lithium action is shown to be time-dependent, since the delay addition of lithium for 5 min to normal bone marrow removes the enhancement usually seen when lithium is given at time zero. The implications of these lithium-induced effects are described.

3H-Imipramine high-affinity binding sites in rat brain. Effects of imipramine and lithium

The specific high-affinity binding of 3H-imipramine to rat brain membranes was investigated. Five weeks of lithium treatment decreased the number of binding sites, but had no effect on the affinity constants. Long-term imipramine treatment had no effect on the number of binding sites but apparently decreased the affinity. The latter effect was probably due to imipramine remaining in the membrane preparation.

Disorders of neuromuscular transmission other than myasthenia gravis

Disorders of neuromuscular transmission in humans are caused by a wide variety of agents including systemic diseases, drugs, environmental toxins, animal envenomation, cations, and hormones. Some are genetically determined. Many are of known etiology. All such disorders interfere with one or more events in the sequence whereby a nerve impulse excites a muscle action potential. In many disorders of neuromuscular transmission, abnormal fatigue occurs, and some cases respond dramatically to treatment. Investigation of the microphysiology, microanatomy, and pharmacology of both normal and diseased neuromuscular junctions has increased our knowledge of these disorders.