Propranolol in the control of schizophrenic symptoms

Protective effect of propranolol and nadolol on social defeat-induced behavioral impairments in rats

Benzodiazepines and SSRIs are considered as standard treatment options for anxiety and depression, hallmarks of Post-Traumatic Stress Disorder (PTSD), although their use is often limited by adverse effects. While promising evidence emerged with β-adrenergic receptor (β-AR) antagonists (or 'β-blockers') and PTSD relief, efficacy issues dampened the excitement. However, we believe it is premature to completely eliminate a beneficial role of β-blockers. Our previous work has suggested that social defeat (SD) results in anxiety-like and depression-like behaviors in rats. Here, using the SD paradigm, we examined the effect of several β-adrenergic receptor antagonists (propranolol, nadolol, bisoprolol) on these behaviors in rats. Following acclimatization, Sprague-Dawley rats received no treatment (for control groups) or treated with ; propranolol (50 mg/kg/day in water), or nadolol (18 mg/kg/day in rats' chow), or bisoprolol (15 mg/kg/day in water). The treatment lasted for 36 days, following which rats were subjected to SD/control exposures (1 week). Later, anxiety-like and depression-like behaviors, social interaction and learning-memory function tests were conducted. SD rats exhibited anxiety- and depression-like behavior as well as learning-memory impairment. Propranolol and nadolol protected SD rats from exhibiting anxiety-or depression-like behaviors. Bisoprolol treatment did not mitigate SD-induced behavioral impairments in rats. Nadolol, propranolol or bisoprolol have no effect in attenuating SD-induced memory function tests. These results suggest that certain 'β-blockers' have the potential to mitigate the negative psychological effects of traumatic events.

Propranolol for the treatment of anxiety disorders: Systematic review and meta-analysis

The effects of propranolol in the treatment of anxiety disorders have not been systematically evaluated previously. The aim was to conduct a systematic review and meta-analysis of randomised controlled trials, addressing the efficacy of oral propranolol versus placebo or other medication as a treatment for alleviating either state or trait anxiety in patients suffering from anxiety disorders. Eight studies met the inclusion criteria. These studies concerned panic disorder with or without agoraphobia (four studies, total n = 130), specific phobia (two studies, total n = 37), social phobia (one study, n = 16), and posttraumatic stress disorder (PTSD) (one study, n = 19). Three out of four panic disorder trials qualified for pooled analyses. These meta-analyses found no statistically significant differences between the efficacy of propranolol and benzodiazepines regarding the short-term treatment of panic disorder with or without agoraphobia. Also, no evidence was found for effects of propranolol on PTSD symptom severity through inhibition of memory reconsolidation. In conclusion, the quality of evidence for the efficacy of propranolol at present is insufficient to support the routine use of propranolol in the treatment of any of the anxiety disorders.

Effects of propranolol on fear of dental extraction: study protocol for a randomized controlled trial

Background

Undergoing an extraction has been shown to pose a significantly increased risk for the development of chronic apprehension for dental surgical procedures, disproportionate forms of dental anxiety (that is, dental phobia), and symptoms of post-traumatic stress. Evidence suggests that intrusive emotional memories of these events both induce and maintain these forms of anxiety. Addressing these problems effectively requires an intervention that durably reduces both the intrusiveness of key fear-related memories and state anxiety during surgery. Moreover, evidence suggests that propranolol is capable of inhibiting “memory reconsolidation” (that is, it blocks the process of storing a recently retrieved fear memory). Hence, the purpose of this trial is to determine the anxiolytic and fear memory reconsolidation inhibiting effects of the ß-adrenoreceptor antagonist propranolol on patients with high levels of fear in anticipation of a dental extraction.

Methods/Design

This trial is designed as a multicenter, randomized, placebo-controlled, two-group, parallel, double-blind trial of 34 participants. Consecutive patients who have been referred by their dentist to the departments of oral and maxillofacial surgery of a University hospital or a secondary referral hospital in the Netherlands for at least two tooth and/or molar removals and with self-reported high to extreme fear in anticipation of a dental extraction will be recruited. The intervention is the administration of two 40 mg propranolol capsules 1 hour prior to a dental extraction, followed by one 40 mg capsule directly postoperatively. Placebo capsules will be used as a comparator. The primary outcome will be dental trait anxiety score reduction from baseline to 4-weeks follow-up. The secondary outcomes will be self-reported anxiety during surgery, physiological parameters (heart rate and blood pressure) during recall of the crucial fear-related memory, self-reported vividness, and emotional charge of the crucial fear-related memory.

Discussion

This randomized trial is the first to test the efficacy of 120 mg of perioperative propranolol versus placebo in reducing short-term (“state”) anxiety during dental extraction, fear memory reconsolidation, and lasting dental (“trait”) anxiety in a clinical population. If the results show a reduction in anxiety, this would offer support for routinely prescribing propranolol in patients who are fearful of undergoing dental extractions.

Trial registration

ClinicalTrials.gov identifier: NCT02268357, registered on 7 October 2014. The Netherlands National Trial Register identifier: NTR5364, registered on 16 August 2015.

Cytochemical Localization of Adenylate Cyclase in Broken Cell Preparations of the Cerebral Cortex

Broken cell preparations derived from rat cerebral cortical grey matter were studied cytochemically to localize adenylate cyclase (AC) activity in subcellular organelle membranes. AC activity was localized by visualizing reaction product in brain particulate fractions by electron microscopy. Activity was found in the endoplasmic reticulum, on the inside of the inner mitochondrial membrane and on both leaflets of the nuclear membrane. Reaction product was found in the postsynaptic density area of most synapses. The reaction product tended to be more prominent in the presence of flouride. A synaptosome-rich fraction was shown to have NE stimulated AC activity which was blocked in vitro by both a α-and an β-blocker and in vivo by propranolol.

Is elevated norepinephrine an etiological factor in some cases of schizophrenia?

A number of hypotheses have been put forth regarding the etiology of schizophrenia, including the dopamine hypothesis, NMDA receptor hypofunction hypothesis, and others. A lesser known theory is that elevated noradrenergic signaling plays a causative role in the disease. This paper briefly re-examines the merits of this hypothesis, including as it relates to some recently published studies. Several lines of evidence are investigated, including: endogenous level studies of norepinephrine (NE); modulation of the disease by noradrenergic drugs; association of the disease with bipolar disorder and hypertension, since these latter two conditions may involve elevated NE transmission; and effects of psychological stress on the disease, since stress can produce elevated release of NE. For many of these lines of evidence, their relationship with prepulse inhibition of startle is examined. A number of these studies support the hypothesis, and several suggest that elevated NE signaling plays a particularly prominent role in the paranoid subtype of schizophrenia. If the hypothesis is correct for some persons, conventional pharmaceutical treatment options, such as use of atypical antipsychotics (which may themselves modulate noradrenergic signaling), may be improved if selective NE transmission modulating agents are added to or even substituted for these conventional drugs.

A comparison of some physiological and psychological effects of propranolol and diazepam in normal subjects

Some central and peripheral effects of orally administered propranolol (60 mg), diazepam (5 mg) and placebo were compared in normal subjects. The central effects measured were changes in magnitude of the contingent negative variation (CNV) and subjective anxiety ratings; the peripheral effects were changes in heart rate, blood pressure, galvanic skin response and hand steadiness. After diazepam there was a decrease in CNV magnitude and in the level of subjective anxiety; there was a slight fall in blood pressure but little change in heart rate. After propranolol, on the other hand, there was no significant change in CNV magnitude or anxiety rating, but a significant fall in heart rate and systolic blood pressure. It is concluded that, at the dosage used, propranolol, unlike diazepam, does not affect the central mechanisms determining CNV magnitude or subjective anxiety. The relationship of this finding to the use of beta-adrenergic receptor blockers in clinical anxiety states is discussed.

Beta-blocker supplementation of standard drug treatment for schizophrenia

BACKGROUND

Many people with schizophrenia or similar severe mental disorders do not achieve a satisfactory treatment response with ordinary antipsychotic drug treatment. In these cases, various add-on medications are used, among them beta-adrenergic receptor antagonists (beta-blockers).

OBJECTIVES

To evaluate the clinical effectiveness of beta-blockers as an adjunct to antipsychotic medication in schizophrenia or similar severe mental disorders.

SEARCH STRATEGY

Publications in all languages were searched from the following databases: Biological Abstracts, CENTRAL of The Cochrane Library, Cochrane Schizophrenia Group's Specialised Register, EMBASE, LILACS, MEDLINE, and PsycLIT. The reference section of papers included were screened.

SELECTION CRITERIA

All randomised controlled trials comparing beta-blockers with placebo as an adjunct to conventional antipsychotic medication for those with schizophrenia.

DATA COLLECTION AND ANALYSIS

Studies were selected and then data extracted, independently, by at least two reviewers. Odds ratios and 95% confidence intervals of homogeneous dichotomous data were calculated with the Peto method. A random effects model was used for heterogeneous dichotomous data. Weighted mean differences were calculated for continuous data.

MAIN RESULTS

Currently the review includes five studies but data are poorly presented and do not evidence any effect of beta-blockers as an adjunct to conventional antipsychotic medication.

REVIEWER'S CONCLUSIONS

At present beta-blockers cannot be recommended in the treatment of schizophrenia. Any possible benefit of adjunctive beta-blockers is obscured by the poor reporting of the included studies. Existing data on beta-blockers as adjunctive medication to antipsychotics for those with schizophrenia should be collected and re-analysed in order to allow confident conclusions about the effect of this treatment or the need for further trials.

A study of enzymes involved in catecholamine metabolism in parents of patients with schizophrenia

The concentrations of serum homovanillic acid (HVA), norepinephrine (NE), tyrosine (Tyr), phenylalanine (Phe) and tryptophan (Trp), and the activities of serum dopamine-beta-hydroxylase (DBH), platelet monoamine oxidase (MAO), and erythrocyte catechol-O-methyl transferase (COMT) were measured in 68 healthy parents who had schizophrenic offspring. The results show a significant correlation between the parents of schizophrenic patients in serum HVA (r=0.38, n=34, p<0.05), NE (r=0.40, n=33, p<0.02), Phe (r=0.44, n=34, p<0.0l), Tyr (r=0.43, n = 34, p <0.02) and DBH activity (r=0.51, n = 30, p <0.005), but do not show a significant correlation in erythrocyte COMT (r=0.01, n=27), platelet MAO (r=0.04, n=23) or serum Trp (r=0.10, n=34). There were no significant correlations in these measurements between randomly matched parents. The present study suggests that both parental sides of schizophrenic patients are likely to have similar alleles associated with the catecholamine pathway, and their ill offspring may possess a double dose of the schizophrenogenic alleles.

Effects of β-adrenoceptor blockers on mitochondrial ATPase activity in guinea pig heart preparations

The effects of three beta-adrenoceptor blockers atenolol, indenolol and nadolol on myocardial mitochondrial ATPase (ATP: phosphohydrolase EC 3.6.1.3) activity were evaluated and compared with that of propranolol in guinea pig heart preparations. Propranolol and indenolol inhibited ATPase activity with IC50 values of 4.4 +/- 0.5 and 5.3 +/- 0.4 mM, respectively. In contrast, however, nadolol and atenolol markedly enhanced mitochondrial ATPase activity. Atenolol increased the enzyme activity by approximately 5, 240 and 950%, while nadolol enhanced it by 13, 280 and 2800% at 100 microM, 1.0 mM and 10.0 mM, respectively. The results indicate that these drugs exhibit two modes of interaction with the mitochondrial ATPase: inhibition by propranolol and indenolol and stimulation by atenolol and nadolol. The inhibitory actions are probably related to the membrane-stabilizing effects and therefore antiarrhythmic actions of the two drugs, while the stimulatory effects of atenolol and nadolol are probably a result of interactions with some component of oxidative phosphorylation or the respiratory chain.

Heterogeneity in plasma homovanillic Acid levels in schizophreniform disorder

Plasma homovanillic acid (pHVA) levels were estimated in 20 cases of schizophreniform disorder, 14 cases of schizophrenia 'on medication' and 17 cases of schizophrenia 'off medication'. A bimodal distribution of pHVA was seen in schizophreniform disorder subjects, suggesting heterogenous groups in terms of dopaminergic function. No significant difference in the pHVA values was seen in the 3 groups, nor was there a relationship between the severity of the illness and the pHVA values; these results suggest plasticity of the dopaminergic system to neuroleptics.

Dopamine and norepinephrine activity in schizophrenia. An integrative perspective

The dopamine (DA) hypothesis of schizophrenia stated that increased DA activity is the primary cause of schizophrenia. Recently, even though increased DA activity is in fact involved in psychotic symptoms and antipsychotic drug response, it has become clear that decreased DA activity is present in remitted and chronic states and may relate to deficit symptoms and cortical lesions. In addition, the norepinephrine (NE) system seems to be involved in symptomatology, antipsychotic drug response, course, and outcome in schizophrenia. This review supports the hypothesis that a disturbance in DA and NE activity regulates schizophrenic behavior. A plethora of DA- and NE-related findings in schizophrenic patients are reviewed in relationship to each other according to basic science data and to presently entertained hypotheses, with emphasis on a neural developmental disturbance interacting with a genetic predisposition shaped by environmental factors.

Propranolol-induced alterations in rat erythrocyte membrane fluidity and apparent phase-transition temperatures. A depth-dependent process

Propranolol-induced alterations of membrane structure were studied in rat erythrocytes using electron spin resonance techniques. Propranolol produced a concentration-dependent change in membrane fluidity in hydrophobic membrane regions, while producing virtually no change in hydrophilic membrane regions. The changes were associated with depth-dependent alterations in "apparent" phase-transition profiles and transition temperatures. The effects of propranolol on these membrane characteristics were similar to those produced by cholesterol. Propranolol fluidized erythrocyte membranes in a depth-specific fashion, by virtue of its association with the rigid phospholipid acyl chains and cholesterol sterol rings in the hydrophilic regions of the membrane, which produced distant perturbations within the hydrophilic regions of the membrane.

Comparison between the Brief Psychiatric Rating Scale and the Manchester Scale for the rating of schizophrenic symptoms

A reliability study was carried out to compare the short Manchester Scale (MS) to the longer Brief Psychiatric Rating Scale (BPRS), to see if similar items scored the same aspect of pathology and to find the sources of error. The raters were a psychiatrist and a psychologist cum medical student; they had recently arrived in Britain, came from different cultures and had not used the scale previously. Comparisons between the scales were made by interviewing the patients separately and together using either one or both scales. The items on the MS showed a higher interrater reliability as compared to the BPRS, both with independent and simultaneous ratings. Items based on observation only correlated poorly as compared to items based on verbal report. Lower between-scale correlations for delusions and affect were observed even where the same rater used the two scales, suggesting that the scales have different meanings for these items. The MS is a suitable alternative to the BPRS for quantifying schizophrenic symptoms.

Potentiation of haloperidol-induced catalepsy by beta-adrenoceptor antagonists in mice

Several clinical papers have reported that beta-adrenoceptor antagonists were useful in the management of schizophrenia and tardive dyskinesia. The present study examined effects of beta-antagonists on haloperidol (HAL)-induced catalepsy using mice in order to study the relationship between beta-antagonists and central dopaminergic functions. Catalepsy was tested by the standard bar test 30 min after intraperitoneal treatment of HAL. Beta-antagonists were administered subcutaneously just after HAL-treatment. Propranolol, alprenolol, oxprenolol and pindolol increased the incidence of catalepsy compared to HAL alone. Atenolol, not penetrating into the brain, and the sedative and hypnotic drug chlordiazepoxide did not potentiate it. These results suggest that the potentiation of HAL-catalepsy by beta-antagonists is based on their central action. Therefore, a central beta-receptor appears to be implicated in the regulation of the central dopaminergic functions.

Does propranolol have an antipsychotic effect? A placebo-controlled study in acute schizophrenia

Thirty-six acute schizophrenics were randomly assigned to dextro (d)-propranolol or placebo in a double blind trial lasting four weeks. All patients had a fixed dose of haloperidol during the first week, which resulted in an initial improvement in both groups. Thereafter, a deterioration towards base-line was seen. Six patients on placebo, but none on propranolol were treatment failures at the end of three weeks (P less than 0.001). Comparison of change in scores from week 2 to 4 showed significantly greater deterioration in the placebo group; d-propranolol thus had a better effect than placebo in sustaining the initial improvement with haloperidol. The overall magnitude of clinical change from pre-treatment scores is small, the majority of the patients showing little or no overall improvement. It is concluded that d-propranolol has a detectable therapeutic effect, which by inference must have a novel pharmacological basis, but this is not as potent as standard neuroleptics.

Mutagenic evaluation of propranolol in somatic and germ cells of mice

The mutagenic effect of an antihypertensive drug, propranolol, was studied on somatic and germ cells of Swiss albino mice. The induction of a significant increase in the frequency of micronuclei in erythrocytes was observed at higher dose levels, whereas, in germ cells, propranolol failed to induce significant chromosomal aberrations at any dose tested.

The effect of propranolol and thioridazine on positive and negative symptoms of schizophrenia

Patients with chronic schizophrenia were treated with either propranolol (640 mg daily) or thioridazine (400 mg daily). In a double-blind study lasting five weeks, propranolol was superior to thioridazine on both psychiatrists' and nurses' ratings. Significant improvements were noted with propranolol in both positive (Type I) and negative (Type II) symptoms.

Semi-empirical conformational analysis of propranolol interacting with dipalmitoylphosphatidylcholine

A semi-empirical conformational analysis is used to compute the conformation of (+)-propranolol inserted in dipalmitoylphosphatidylcholine. In a first step, the minimal conformational energy of the isolated molecule at the hydrocarbon-water interface is calculated as the sum of the contributions resulting from the Van der Waals, the torsional, the electrostatic and the transfer energies. Five pairs of conformers of minimal energy are determined. They are compared to data available from other experimental approaches. In a second step, they are assembled with dipalmitoylphosphatidylcholine at the interface. Although propranolol is considered in its protonated form, the electrostatic interaction with dipalmitoylphosphatidylcholine is negligible as compared to the Van der Waals interaction. The area occupied per propranolol molecule is between 0.53 and 0.64 nm2/molecule. In the most probable modes of insertion of propranolol into the lipid layer, the naphthyl moiety of the compound interacts with the lipid acyl chains. The protonated amino group is located in the vicinity of the phosphate residue possibly causing an electrostatic interaction.

A clinical trial of the beta blocker propranolol in premature ejaculation

Twelve male patients, with a primary complaint of premature ejaculation in a setting of chronic anxiety with prominent somatic manifestations, participated in a double-blind trial: propranolol against placebo. The study consisted of 5 X 4 week phases: run-in, propranolol or placebo--120 mg/day allocated randomly, wash-out; placebo or propranolol and run-out, in a balanced design. Anxiety was rated initially, and every 2 weeks, throughout the trial using the Hamilton Rating Scale. Sitting blood pressure and pulse were also noted. The time to coital ejaculation (every 3 days) was recorded using a stopwatch, and subjects were also required to rate "overall coital satisfaction" and "quality of erection". Neither prematurity nor other signs/symptoms of anxiety improved on the preparations, which were statistically equivalent. Moderate beta-blockade was achieved with propranolol as evidenced by a median reduction in pulse rate of 5 beats/min.

The effect of propranolol on CSF amine metabolites in psychiatric patients

In view of the central side effects of beta-adrenoceptor blocking agents and their alleged antipsychotic action in the absence of DA receptor blockade, it is important to establish which neurotransmitters are likely to be involved. Previous animal and patient studies have, however, produced conflicting data on this point. The changes in CSF HVA, 5HIAA and MHPG during treatment with propranolol (960 mg/day) in chronic schizophrenic patients were monitored on four occasions over 30 days. Clinical changes were monitored by the Wing and Krawiecka Scales and motor activity was assessed by pedometer. CSF HVA levels were significantly increased by propranolol and the rise continued throughout the 30 day period. There were no significant changes in the other metabolites. There was no evidence of any therapeutic benefit from propranolol treatment in these patients. These findings may explain the central side-effects and occasional reports of schizophreniform psychosis after propranolol, since an increase in DA turnover occurs without DA receptor blockade.

Propranolol in schizophrenia

1. 15 schizophrenic patients diagnosed according to criteria of I.C.D.-9 were treated with d1-propranolol in a 4 week open study. 2. A fixed dose schedule was followed and a maximum dose of 1920 mg/day was reached by day 17. 3. Results revealed a significant reduction in core schizophrenic symptoms of CPRS & BPRS starting between 1st and second weeks of therapy. Higher doses were well tolerated and serious bradycardia occurred only in 3 patients. 4. The implications of these results are discussed.

Beta-adrenoceptor blocking drugs: adverse reactions and drug interactions

Beta adrenoceptor blocking drugs are relatively well tolerated and adverse reactions to them are not common. The ones that do occur are reviewed in this paper under the following headings: Short term adverse reactions, drug interactions, long term adverse reactions, risks in pregnancy and hazards of abrupt withdrawal. Predictable short term effects may be caused either by the actions of these drugs on the beta 1- or beta 2-receptors. The beta 1 adverse effects are hypotension, bradycardia and cardiac failure; these are best avoided by not giving beta-adrenoceptor blocking drugs to susceptible patients with cardiac disease. The beta 2 adverse effects on the bronchi, the peripheral arteries and various metabolic functions may be reduced to some extent by using a relatively cardioselective drug. Unpredictable short term effects such as fatigue, sexual dysfunction and gastrointestinal symptoms may occur but are not common problems with this group of drugs. Similarly, serious drug interactions are infrequent. Under the heading of long term adverse effects the practolol problem and the risk of causing malignant disorders have been considered. There is no evidence that any of the currently available drugs will cause either a practolol syndrome or malignant disease in man. However, the need for careful appraisal by drug regulatory bodies and continued vigilance by all prescribers of beta-adrenoceptor blocking drugs remains. The possible adverse effects of treatment during pregnancy are also considered. It now appears that beta-adrenoceptor drugs can be used safely in pregnancy but since neonatal bradycardia and hypoglycemia may occur, care should be taken to look for these complications. A serious deterioration may occur when beta-adrenoceptor drugs, given to patients with significant ischemic heart disease, are suddenly stopped. This is a rare occurrence but prescribers should be aware of it.

Propranolol-induced structural changes in human erythrocyte ghost membranes. A spin label study

The effect of propranolol on the structure of human erythrocyte membranes was studied using a spin labeling technique. Changes in electron spin resonance spectra of spin labeled membrane proteins were detected at concentration of the drug corresponding to its antihemolytic effect on intact erythrocytes. The character of spectral changes suggests that propranolol-induced alterations in organization of membrane proteins are connected mainly with perturbation of protein sites located on membrane surface. Propranolol also produces a decrease in order parameter of membrane lipids. The disordering effect is, however, small and detectable only at relatively high concentrations of the drug.

Studies on the inhibition by propranolol of some human erythrocyte membrane enzymes and plasma cholinesterase

Human erythrocyte acetylcholinesterase and the plasma cholinesterase variants are not only inhibited by propranolol but have been found to show stereospecificity for its isomers. The erythrocyte enzyme has a greater affinity for the L-isomer than either the racemate or the D-isomer. In contrast the plasma cholinesterases have greater specificity for the D-isomer than the other isomer or racemate. The usual enzyme shows greater stereospecificity than the atypical enzyme and these findings present additional evidence that these enzyme variants differ in structure at the catalytic active site. Neither Na+ + K+ -ATPase nor Mg2+-ATPase show stereo-specificity for the isomers of propranolol although both enzymes are inhibited by the drug. The action of the drug on the four enzymes in blood samples obtained from patients having Huntington's disease was found to be identical to those observed on the enzymes in blood samples from healthy controls.

Efficacy of propranolol on schizophrenic thought disorder

15 schizophrenic patients were treated with dl-propranolol in a 4 week open study. Dosage was gradually increased over a period of 17 days to 1920 mg/day. Improvements were rated on Thought Disorder Scores (A & B) of the MBPRS and GPRS subscale for schizophrenia. Majority of the patients showed a 50% improvement in terms of their residual scores by the 4th week of treatment and the side effects experienced were minimal.

Beta-blockers in the treatment of neurological and psychiatric disorders

Beta-blockers, originally introduced into clinical practice for the treatment of cardiovascular disorders, are being increasingly advocated in the treatment of diverse neurological and psychiatric conditions. Thus, propranolol and certain other beta-blockers have been shown to be effective, and may be the drugs of choice, in the treatment of benign essential tremor and the prevention of recurrent migraine attacks. These drugs also have a useful role to play in the treatment of anxiety and alcohol withdrawal states, although beta-blockers have not come into general use in these conditions. The action of propranolol and related drugs in these neurological and psychiatric conditions is generally considered to be mediated by blockade of peripheral beta-adrenergic receptors, although other effects, either central or peripheral, may also be involved. The use of beta-blockers in the treatment of psychosis remains controversial. Current evidence does not support the use of propranolol in schizophrenia, but further studies in mania are warranted.

Essential tremor

Essential tremor, including the juvenile and senile variations, may be a result of a disorder of the servomechanism that controls physiologic tremor. Hands and arms are affected most commonly, and the tremor can vary in amplitude as well as frequency. Long-term treatment with propranolol has been helpful for some patients, although older patients are less likely to benefit. Other drugs and behaviour modification therapy have been less successful. Surgical treatment is effective but should probably be reserved for severe cases. An effective instrument for measuring the subjective and objective aspects of the tremor is still needed, as is an effective long-term method of treatment.

Interaction of propranolol with model phospholipid membranes. Monolayer, spin label and fluorescent spectroscopy studies

The interaction of propranolol with model phospholipid membranes was studied using various experimental techniques. The partition coefficient of propranolol in the negatively charged membranes of vesicles prepared from phosphatidylserine and phosphatidic acid was found to be more than 20-times higher than in neutral phosphatidylcholine membranes. Preferential interaction of propranolol with acidic phospholipid membranes was confirmed using the monolayer compression isotherm technique and the spin-labelling method. Phosphatidylserine monolayers were markedly expanded even at a relatively low drug concentration (5 . 10(-6) M). In contrast, the effect of propranolol on phosphatidylcholine monolayers was much smaller, being detectable only at a higher concentration of the drug (1 . 10(-4) M). Spin-labeling experiments show that propranolol exerts marked ordering effect on bilayers prepared from acidic phospholipids and does not change the order parameter of phosphatidylcholine membranes. The dependence of the propranolol fluorescence spectrum on the polarity of the solvent allowed us to identify the intercalation region of the drug in the membrane. The fluorophore moiety of propranolol was found to be localized in the lipid polar head groups region of the bilayer. The role of electrostatic and hydrophobic effects in propranolol-membrane interaction is discussed and the effect of propranolol on the ordering of phospholipid bilayers is compared with the effects of other anesthetic-like molecules.

(Des-Tyr)-gamma-endorphin in the treatment of schizophrenia

Inj. (Des-Tyr1)-γ-endorphin was used in a pilot study over a period of 12 days for the treatment of 11 schizophrenics and the assessments were carried out using standardized rating scales. Only 2 patients showed an improvement. Euphoria and excitement were observed in 3 patients. The findings are discussed in contrast to the earlier reports of a dramatic improvement with the compound.

Propranolol differentially blocks the methamphetamine-induced depression of tryptophan hydroxylase in various rat brain regions

Basal tryptophan hydroxylase activity was measured in several serotonergic nerve terminal regions of the rat brain and was found to vary from one terminal region to another. Acute administration of methamphetamine produced a marked decrease in tryptophan hydroxylase activity in all serotonergic nerve terminal regions of rat brain examined. This decrease was antagonized in a regionally selective manner by propranolol. In contrast, haloperidol did not produce a similar antagonism. The results are discussed in the context of the previously reported efficacy of large doses of propranolol in some schizophrenic patients.

Effect of propranolol and phenothiazines on electrodermal orienting and habituation in schizophrenia

Bilateral electrodermal orienting responses were measured to repeated auditory stimuli in schizophrenic patients and controls. In 3 studies phasic activity to moderate intensity sounds of patients on no drugs or phenothiazines was predominantly hyper- or hypo-responsive. Controls showed moderate or slow habituation. Propranolol was found to facilitate habituation in slow habituators and to reinstate responses in half of non-responders, especially when given as the sole drug. The effects seldom had a counterpart in changes in non-specific responses or levels of skin conductance. Modulatory influences on stimulus and response processing and on lateral asymmetries in responses may underlie propranolol's efficacy in treating schizophrenia.

DL-propranolol and chlorpromazine following admission for schizophrenia. A controlled comparison

Similar improvement followed when propranolol and chlorpromazine were randomly used as the first drug after admission. Forty-six patients with florid symptoms of schizophrenia were assigned at random to have either racemic propranolol (24) or chlorpromazine (22). Each individual's drug was adjusted to an optimal dose, and the progress of the groups was followed for 12 weeks. Thirty-five patients remained in the study for 6 weeks, and 27 for 12 weeks. By weeks 6 and 12 the total schizophrenia scores on a modified Brief Psychiatric Rating Scale had improved significantly when the results from both groups were combined. The numbers leaving the study, and the amount and rate of improvement, were similar for both groups, but with a possible advantage to chlorpromazine. Side-effects, which usually were mild, were commoner in the chlorpromazine group.