Maprotiline Treatment Research Articles

Maprotiline Ameliorates High Glucose-Induced Dysfunction in Renal Glomerular Endothelial Cells.

Maprotiline is an antidepressant that has been found to cause hypoglycemia. However, the effect of maprotiline on diabetic nephropathy (DN) has not been investigated. Here, we explored the effect of maprotiline on human renal glomerular endothelial cells (HRGECs) in response to high glucose (HG) stimulation. We found that maprotiline attenuated HG-induced oxidative stress in HRGECs with decreased reactive oxygen species production and increased superoxide dismutase activity. Maprotiline repressed the HG-induced expression of cyclooxygenases 2 at both mRNA and protein levels in HRGECs. The increased thromboxane B2 level and decreased 6-keto-prostaglandin F1α level induced by HG were significantly attenuated by maprotiline treatment. Maprotiline also prevented the HG-induced increase in the permeability of HRGECs and the decrease in the zonula occludens-1 expression and downregulated HG-induced increase in the expression of protein kinase C-α (PKC-α) in HRGECs. This protective effect of maprotiline on HG-induced HRGECs dysfunction was abolished by overexpression of PKC-α. In conclusion, maprotiline displayed a protective effect on HG-challenged HRGECs, which was mediated by the regulation of PKC-α. These findings provide further evidence for the potential use of maprotiline for the treatment of DN.

Maprotiline ameliorates isoflurane-induced microglial activation via regulating triggering receptor expressed in myeloid cells 2 (TREM2)

ABSTRACT Isoflurane-induced neurotoxicity has attracted much interest. Recent studies suggest that isoflurane causes microglial activation, resulting in an inflammatory response and microglial insult. Maprotiline is a novel drug that has been licensed as an antidepressant with considerable anti-inflammatory activity. However, it is still unknown whether maprotiline possesses a protective effect against isoflurane-induced microglial insult. Here, we found that maprotiline ameliorated isoflurane-caused reduction in BV2 microglial cell viability and lactate dehydrogenase (LDH) release. Maprotiline mitigated isoflurane-induced oxidative stress by inhibiting reactive oxygen species (ROS) production and increasing superoxide dismutase (SOD) activity. Isoflurane-induced expression and production of inflammatory markers including tumor necrosis factor (TNF-α), interleukin (IL)-1β, cyclooxygenase‐2 (COX-2), and prostaglandin E2 (PGE2) were decreased in maprotiline-treated cells. Maprotiline inhibited the mRNA and protein levels of Iba1, a marker of microglial activation, in isoflurane-induced BV2 cells. Maprotiline treatment restored isoflurane-induced reduction of TREM2 in BV2 microglial cells. In addition, the knockdown of TREM2 abolished the beneficial effects of maprotiline against isoflurane. Collectively, maprotiline exerted protective effects against isoflurane-caused oxidative stress, inflammatory response, and cell injury via regulating TREM2. These findings show that maprotiline prevented the isoflurane-induced microglial activation, indicating that maprotiline might be used as an optimal therapeutic agent for preventing the isoflurane-caused neurotoxicity.

Role of prefrontal cortical calcium-independent phospholipase A2 in antinociceptive effect of the norepinephrine reuptake inhibitor antidepresssant maprotiline

The prefrontal cortex is essential for executive functions such as decision-making and planning. There is also accumulating evidence that it is important for the modulation of pain. In this study, we investigated a possible role of prefrontal cortical calcium-independent phospholipase A2 (iPLA2) in antinociception induced by the norepinephrine reuptake inhibitor (NRI) and tetracyclic (tricyclic) antidepressant, maprotiline. Intraperitoneal injections of maprotiline increased iPLA2 mRNA and protein expression in the prefrontal cortex. This treatment also reduced grooming responses to von-Frey hair stimulation of the face after facial carrageenan injection, indicating decreased sensitivity to pain. The antinociceptive effect of maprotiline was abrogated by iPLA2 antisense oligonucleotide injection to the prefrontal cortex, indicating a role of this enzyme in antinociception. In contrast, injection of iPLA2 antisense oligonucleotide to the somatosensory cortex did not reduce the antinociceptive effect of maprotiline. Lipidomic analysis of the prefrontal cortex showed decrease in phosphatidylcholine species, but increase in lysophosphatidylcholine species, indicating increased PLA2 activity, and release of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) after maprotiline treatment. Differences in sphingomyelin/ceramide were also detected. These changes were not observed in maprotiline-treated mice that received iPLA2 antisense oligonucleotide to the prefrontal cortex. Metabolites of DHA and EPA may help to strengthen a known supraspinal antinociceptive pathway from the prefrontal cortex to the periaqueductal gray. Together, results indicate a role of prefrontal cortical iPLA2 and its enzymatic products in the antinociceptive effect of maprotiline.

Screen of FDA-approved drug library identifies maprotiline, an antibiofilm and antivirulence compound with QseC sensor-kinase dependent activity in Francisella novicida

Development of new therapeutics against Select Agents such as Francisella is critical preparation in the event of bioterrorism. Testing FDA-approved drugs for this purpose may yield new activities unrelated to their intended purpose and may hasten the discovery of new therapeutics. A library of 420 FDA-approved drugs was screened for antibiofilm activity against a model organism for human tularemia, Francisella (F.) novicida, excluding drugs that significantly inhibited growth. The initial screen was based on the 2-component system (TCS) dependent biofilm effect, thus, the QseC dependence of maprotiline anti-biofilm action was demonstrated. By comparing their FDA-approved uses, chemical structures, and other properties of active drugs, toremifene and polycyclic antidepressants maprotiline and chlorpromazine were identified as being highly active against F. novicida biofilm formation. Further down-selection excluded toremifene for its membrane active activity and chlorpromazine for its high antimicrobial activity. The mode of action of maprotiline against F. novicida was sought. It was demonstrated that maprotiline was able to significantly down-regulate the expression of the virulence factor IglC, encoded on the Francisella Pathogenicity Island (FPI), suggesting that maprotiline is exerting an effect on bacterial virulence. Further studies showed that maprotiline significantly rescued F. novicida infected wax worm larvae. In vivo studies demonstrated that maprotiline treatment could prolong time to disease onset and survival in F. novicida infected mice. These results suggest that an FDA-approved drug such as maprotiline has the potential to combat Francisella infection as an antivirulence agent, and may have utility in combination with antibiotics.

A case report of hyponatremia associated with maprotiline treatment

Background: Maprotiline is a tricyclic antidepressant (sometimes classifi ed as a tetracyclic antidepressant), which is predominantly a norepinephrine/noradrenaline reuptake inhibitor, commonly prescribed for depression. Aim: To present a female patient with depressive episode and occurrence of hyponatremia during the maprotiline treatment. Case Report: A 62-year-old female was diagnosed with depressive episode four years ago. She was treated ambulatory with maprotiline 50mg/day and bromazepam 6mg/ day, from local psychiatrist. The patients also used enalapril 2x10 mg/day, metoprolol 2x50 mg/day, nifedipine 5 mg/day and simvastatin 20 mg/day for treating hypertension and dyslipidemia. After about 12 months of maprotiline use she was hospitalized at the Endocrinology unit of a local hospital due to appearance of confusion, unstable walking, cramps, as well as an increase in blood pressure. Then diagnosed hyponatremia (serum sodium level-112 mmol/L), corrected (137 mmol/L) by using parenteral therapy. The patient continued to use maprotiline without consultation with her psychiatrist. After one year, the patient was hospitalized at the Endocrinology unit of tertiary level due to detailed re-examination because of recurrent hyponatramia (117 mmol/L), corrected (136 mmol/L) by ambulatory use of parenteral therapy at a local hospital. Water test load was used and the Syndrome of inappropriate antidiuretic hormone secretion was diagnosed. Insulin Tolerance Test showed preserved the integrity of the hypothalamic-pituitary-adrenal axis. Antidepressant mirtazapine (15 mg/ day) was introduced due to recurrence of depression. Gradual reduction of depressive symptoms was observed to mirtazapine. Antihypertensive therapy, restriction of fl uid intake and dietary regimen were still applied. Serum sodium concentrations were in the normal ranges over the past 18 months. Conclusion: Serum sodium level should be measured before and during the therapy with any class of antidepressants, especially in those patients with increased risk of the hyponatremia occurrence.

Maprotiline treatment differentially influences cardiac β-adrenoreceptors expression under normal and stress conditions

Alterations in cardiac function were observed in antidepressants treated patients and published in several clinical reports. These detected changes could be either a consequence of the treatment or of depression itself, which has already been proved to be a risk factor in heart diseases. In order to determine a possible influence of chronic treatment with norepinephrinergic reuptake inhibitor, maprotiline, on the heart, we investigated gene expression of cardiac β-adrenoceptors both in controls and in animals with signs of depression. The rats were divided into two groups, unstressed controls and those exposed to chronic unpredictable mild stress (CUMS). The groups were further divided into two subgroups, one receiving daily intraperitoneal injections of vehicle (sterile water) and another one maprotiline (10 mg/kg) for four weeks. Tissue samples were collected after the last application. Gene expression of cardiac β1- and β2-adrenoceptor was determined using Real-time RT-PCR analysis. Our results show that in control animals expression of both adrenoreceptors was decreased in the right atria after 4 weeks of maprotiline application. Contrary, the same treatment led to a significant increase in expression of cardiac β1-adrenoceptor in the stressed rats, with no change in the characteristics of β2-adrenoceptor. Our findings might reflect the that molecular mechanisms are underlying factors involved in the development of cardiovascular diseases linked with antidepressant treatment.

Complex visual disturbances during maprotiline treatment

ALTHOUGH MAPROTILINE IS no longer a first-choice agent for treating major depression, it is sometimes used in combination with a selective serotonin re-uptake inhibitor in treatment-resistant depression. Here, we report the case of a woman who developed complex visual disturbances after maprotiline use. At the age of 63, the patient began to experience depression and was treated at Jichi Medical University Hospital. At that time, the medication did not have any effect, and she underwent electroconvulsive therapy, which proved effective. The patient was readmitted at the age of 64 because depression recurred. At the time of admission, her medication history was as follows: milnacipran, trazodone, and amitriptyline. After the admission, she was prescribed only trazodone 150 mg/day. Because no marked improvement was observed, maprotiline was given at 25 mg/day, and the dose was increased up to 100 mg/day. Maprotiline at a dose of 75 mg triggered pareidolia (‘seeing shadows looking like someone's face’), visual hallucination (‘seeing faces of people and animals in the mirror’), and visual disturbance (‘feeling that floors and walls are approaching’). The patient was aware that these experiences were not real images. Because they appeared after maprotiline use, the complex visual disturbances were suspected to be a side-effect of maprotiline. Therefore, maprotiline was reduced and then was discontinued, following which the symptoms disappeared. Magnetic resonance imaging, single-photon-emission computed tomography, and electroencephalography were normal. Hori et al. reported a case of symptoms of visual perseveration induced by maprotiline.1 The present patient experienced pareidolia, visual hallucination, and visual disturbance. The symptoms reported in both cases were not exactly the same, but the present case is the second report of visual disturbances induced by maprotiline. Some authors have put forward hypotheses to explain the mechanisms underlying maprotiline-induced visual impairment. The symptoms in the Hori et al. report were thought to be caused by the anticholinergic effect of maprotiline. Maprotiline is thought to be a noradrenaline re-uptake inhibitor, whereas hallucinations result from an increase in dopamine levels. Kihara and Ikeda found an increase in dopamine levels due to maprotiline.2 Their findings were consistent with those of Carboni et al., who stated that the increase in dopamine levels was caused by a carrier of the noradrenaline uptake inhibitor.3 The complex visual disturbances in the present case may have been associated with maprotiline-induced increase in dopamine levels or an anticholinergic effect. Nevertheless, visual impairment is a rare side-effect of antidepressants, and physicians should be aware of this rare phenomenon.

Role of prefrontal cortical calcium independent phospholipase A2 in antidepressant-like effect of maprotiline

There is increasing interest in the pathophysiology and neurochemistry of the prefrontal cortex (PFC) in depression. Blood flow and metabolism are decreased in the PFC of patients with depression compared to controls. Changes in long-chain polyunsaturated fatty acids (PUFAs) are also associated with depression. This study was conducted to elucidate a possible role of PFC activity of an enzyme involved in the release of docosahexaenoic acid (DHA), i.e. calcium-independent phospholipase A2 (iPLA₂), in the effects of the norepinephrine reuptake inhibitor (NRI) antidepressant, maprotiline, in mice. Treatment of Balb/C mice with maprotiline for 4 wk resulted in reduction in the level of behavioural despair, as determined by decreased immobility and increased climbing during the forced swim test. In contrast, mice treated with maprotiline plus bilateral prefrontal cortical injections of antisense oligonucleotide to iPLA₂, showed significantly increased immobility and decreased climbing, to levels comparable to saline-treated controls, indicating abolishment of the antidepressant-like effect of maprotiline. Lipidomic analyses showed significant decreases in phosphatidylcholine species containing long-chain PUFAs and increases in lysophosphatidylcholine after maprotiline treatment, indicating increased PLA₂ activity and endogenous release of eicosapentaenoic acid (EPA) or DHA after maprotiline treatment. These changes in lipid profiles were absent in mice that received maprotiline and PFC injections of antisense oligonucleotide to iPLA₂. Together, the results indicate that PFC iPLA₂ activity plays an important role in the antidepressant-like effect of maprotiline, possibly through endogenous release of long-chain PUFAs.

Maprotiline induced weight gain in depressive disorder: Changes in circulating ghrelin and adiponectin levels and insulin sensitivity

Agents such as clozapine, olanzapine and mirtazapine frequently trigger an increase in body weight. Though the mechanisms have not been thoroughly clarified, recent studies indicate a role for ghrelin in regulation of appetite and weight gain. We investigated the relation of maprotiline induced weight gain to serum ghrelin and adiponectin levels, as well as insulin resistance in lean subjects with depressive disorder. A total of 40 male lean subjects with depressive disorder were treated with maprotiline (150 mg/day) for 30-days. Clinical data, fasting plasma glucose, lipids, insulin levels, serum ghrelin and adiponectin concentrations were determined before and after treatment. Insulin resistance was estimated using the homeostasis model assessment (HOMA) formula. After 30 days of treatment with maprotiline, mean body mass index increased significantly. Blood ghrelin and insulin levels and HOMA indexes increased, and adiponectin concentration decreased ( p < 0.001, for all) after the treatment period. Changes in ghrelin levels correlated neither of the parameters tested; whereas decrease in plasma adiponectin was associated with an increase in BMI ( r = − 0.671, p < 0.001). In conclusion, the results indicate that treatment of lean patients with depressive disorder with maprotiline results in an increase in serum ghrelin and reduction in adiponectin levels. Weight gain due to maprotiline treatment may be related to its negative effects on the metabolic variables.

Comparisons of glucose–insulin homeostasis following maprotiline and fluoxetine treatment in depressed males

Background To investigate the effects of antidepressants on glucose–insulin homeostasis, we provided homogenous situation and performed standard procedures to assess the interactions of antidepressants and glucose regulation during hospitalization. Methods Twenty-three non-diabetic depressed males were recruited and assigned to two groups based on the antidepressants received (maprotiline n = 11, fluoxetine n = 12). The severity of depression was evaluated using a 21-item Hamilton depression rating scale (HAM-D). Before and after the 4-week treatment, participants underwent 75-g oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIGT). Insulin sensitivity ( S I), glucose effectiveness ( S G), acute insulin response (AIR), and disposition index (DI) were estimated using minimal model method. Results The HAM-D scores were reduced significantly ( P < 0.005) after antidepressant treatment. Following maprotiline treatment, the body weight and BMI were significantly increased ( P = 0.02). Individuals treated with maprotiline displayed a significantly increased AIR (3239 ± 682 vs. 4698 ± 597 pmol; P = 0.04) during the FSIGT. Limitations The sample size was limited. Furthermore, the study was conducted in the early phase of depression-treated course. Conclusions The results suggest that the β-cell function is hyperbolic in order to offset the insulin resistance following maprotiline treatment. Our findings imply that norepinephrine reuptake inhibitor (NRI) antidepressants might attenuate insulin sensitivity.

G olf protein levels in rat striatum are increased by chronic antidepressant administration and decreased by olfactory bulbectomy

There are many studies of the mechanisms of antidepressants; however, most of these studies were conducted on the hippocampus or frontal cortex. In the present study, we hypothesized that the nucleus accumbens and caudate/putamen might be major targets for antidepressant effects. Thus, we focused on G olf protein, a stimulant α-subunit of G protein that is coupled with the dopamine D1 receptor and specifically expressed in the striatum (nucleus accumbens, caudate/putamen and olfactory tubercle) in the rat brain. We examined the effects of chronic administration of imipramine, fluvoxamine, maprotiline and, as a negative control, cocaine on the level of G olf protein in the rat striatum. We also examined the effect of olfactory bulbectomy. Chronic imipramine treatment (10 mg/kg for 2 or 4 weeks) significantly increased the level of G olf in the striatum (by 17% or 18%, respectively), although this increase was not apparent after only 1 week of treatment. The time course of these changes corresponded well to that of the clinical efficacy of imipramine. Chronic fluvoxamine and maprotiline treatment (20 mg/kg for 2 weeks) also significantly increased the level of G olf (by 9% and 25%, respectively), but cocaine did not alter it significantly. Bulbectomy decreased the G olf protein level by 9%. The increases in G olf protein after chronic administration of these three different classes of antidepressants and the decrease after bulbectomy suggest that G olf protein may play an important role in the antidepressant effect.

Changes in AMPA subunit expression in the mouse brain after chronic treatment with the antidepressant maprotiline: a link between noradrenergic and glutamatergic function?

Potentiation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor function has been proposed as being useful in the treatment of depression, but thus far, little is known about the possible changes in AMPA receptor expression in the brain, after antidepressant treatment. The present study was carried out to study the expression of AMPA receptor subunits in different brain regions of mice that had been chronically injected with maprotiline. The latter is a modified tricyclic antidepressant that functions as a noradrenaline uptake inhibitor. Daily intraperitoneal injection with 10 mg/kg maprotiline for 30 days resulted in significantly increased GluR1 and GluR2/3 subunit expression in the nucleus accumbens and dorsal striatum as detected by immunohistochemistry; and significantly increased GluR1 and GluR2/3 expression in the hippocampus, as demonstrated by Western blot analysis. No change, or a decrease in GluR2 expression was detected in all the brain regions by both immunohistochemistry and Western blots. The increase in GluR1 and GluR2/3, but no increase in GluR2 subunits suggests that there could be an increase in calcium permeability of AMPA receptors in limbic/striatal brain regions after maprotiline treatment. This could lead to increased synaptic activity or plasticity in the hippocampus and striatum, and may underlie the therapeutic effect of maprotline, and possibly, other antidepressant drugs.

Plasma free 3-methoxy-4-hydroxyphenylglycol predicts response to fluoxetine

This study was designed to investigate the relationship between platelet serotonin (5-HT) and plasma free 3-methoxy-4-hydroxyphenylglycol (MHPG) measures in depressed outpatients obtained from the same patient with unipolar depression during the pretreatment period and subsequent response to 6 weeks of treatment with either fluoxetine or maprotiline. Compared to the nonresponder group, the fluoxetine responders showed significantly higher pretreatment levels of MHPG, but no difference in pretreatment 5-HT levels. There were no significant differences in either 5-HT or MHPG levels between maprotiline responders and nonresponders. As to posttreatment levels, there were no between-group differences in 5-HT or MHPG between responders and nonresponders to either fluoxetine or maprotiline. When the relationships between changes in 5-HT or MHPG levels and treatment response were examined, 5-HT values showed a marked decrease in both fluoxetine responders and nonresponders, but no significant changes were found in the maprotiline treatment groups. On the other hand, MHPG levels in the fluoxetine nonresponders tended to increase (borderline significance), whereas the MHPG levels for fluoxetine responders and maprotiline responders and nonresponders were unaffected from pre- to posttreatment. Pretreatment levels of plasma free MHPG appear to predict response to fluoxetine.

Effectiveness and Tolerance of the Hypericum Extract LI 160 Compared to Maprotiline: A Multicenter Double-Blind Study

A randomized, double-blind study examining the effectiveness and tolerance of a standardized hypericum preparation when compared to maprotiline was performed in a group of 102 patients with depression, in accordance with ICD-10, F 32.1. The study was conducted in the offices of neurology and psychiatry specialists. The patients received, over a period of 4 weeks, either 3 x 300 mg of the hypericum extract or 3 x 25 mg maprotiline pills of identical appearance. Effectiveness was determined using the Hamilton Depression Scale (HAMD), the Depression Scale according to von Zerssen (D-S), and the Clinical Global Impression Scale (CGI). The total score of the HAMD scale dropped during the 4 weeks of therapy in both treatment groups by about 50%. The mean values of the D-S scale and the CGI scale showed similar results, and after 4 weeks of therapy, no significant differences in either treatment group were noticed. The onset of the effects occurred up to the second week of treatment, but were observed earlier with maprotiline than with the hypericum extract. On the other hand, maprotiline treatment resulted in more cases of tiredness, mouth dryness, and heart complaints.

Predicting Therapeutic Results with Levoprotiline and Maprotiline in Major Depression: The Role of the Outcome Criteria

We describe a double-blind study involving 58 in-patients with major depression (DSM-III). After one week on placebo, the patients were randomly assigned to either levoprotiline or maprotiline treatment for three weeks. In the next three weeks, responders were maintained on the same medication and non-responders were shifted to treatment with the complementary drug. After the initial three weeks' treatment, 31% of levoprotiline patients and 58% of maprotiline patients had responded. Both in the initial three-week period and after shifting non-responders to the complementary drug, there were significant differences in favour of maprotiline. The comparison of properties of different outcome criteria in prediction analyses shows that the final score gives the best agreement with global evaluation; using the delta score (final minus baseline) or ratio score (final/baseline) as the outcome criterion may yield paradoxical results.

A Case of Neuroleptic Malignant Syndrome with Acute Renal Failure after the Discontinuation of Sulpiride and Maprotiline.

A 46-year-old man developed neuroleptic malignant syndrome with acute myoglobinuric renal failure after the discontinuation of sulpiride and maprotiline treatment. He showed the characteristic features of hyperpyrexia, altered consciousness, muscle rigidity, and autonomic dysfunction. Laboratory data showed lysis of skeletal muscle cells and renal impairment. Muscle biopsy revealed necrosis and regenerative changes in muscle fibers. Renal biopsy showed focal tubulitis and interstitial infiltration of small inflammatory cells. The combination of sulpiride and maprotiline has not previously been reported to be the cause of neuroleptic malignant syndrome and acute myoglobinuric renal failure.

The effect of antidepressants on immune function in mice

Depression or its treatment with antidepressant agents may have an impact on the normal function of the immune system. To address this issue in an animal model, we studied the effect of maprotiline and desipramine treatment of mice on several immunological activities associated with host resistance to cancer and infections. Our results indicate that chronic maprotiline treatment depressed natural killer (NK) cell function, measured in vivo as clearance of tumor cells from the lung or in vitro as cytolytic activity. Cell-mediated immunity, measured as delayed hypersensitivity in vivo and T and B lymphocyte proliferative responses in vitro, was largely unaffected. Although antidepressant toxicity at high concentrations inhibited T, B, and NK cell activity, it is unlikely that this is the basis for the in vivo effects.

Clomipramine and maprotiline in the treatment of chronic idiopathic pain syndromes; a comparison and biological markers

This article shortly summarizes results from a clinical trial in idiopathic pain syndromes. In order to evaluate the clinical effect of antidepressants in patients with idiopathic pain syndromes a noradrenaline reuptake inhibitor (maprotiline) and a serotonin reuptake inhibitor (clomipramine) were given to 70 patients for six weeks in a randomized double-blind multicentre trial. Eighteen patients were excluded during the study. In addition to pain, 16 depressive symptoms were observed. Clomipramine-treated patients showed an overall improvement of 63%, and maprotiline-treated patients reported a 36% improvement (p<0.05). Side effects were generally mild. Eight patients in the clomipramine group and one in the maprotiline group were excluded due to side effects. The 3H-imipramine receptor binding to platelets in chronic idiopathic pain patients was measured. The Bmax values were decreased by 11% prior to treatment. Maprotiline treatment tended to increase the values towards those of healthy controls, while...

Chronic treatment with antidepressant drugs and ECT differentially modifies the hypothermic action of clonidine and guanfacine.

The hypothermia inducing action of clonidine and guanfacine was abolished by yohimbine and idazoxan pretreatment which suggests an alpha 2-adrenoceptor involvement in this effect. The effects of acute and chronic treatment with the antidepressant drugs desipramine (DMI), amitriptyline (AMI), maprotiline (MAP), mianserin (MIAN), iprindol (IPR), alaproclate (ALA) and electroconvulsive treatment (ECT) on the hypothermic action of the alpha 2-adrenoceptor agonists clonidine and guanfacine were studied. Acute administration of MIAN potentiated clonidine induced hypothermia whereas acute MIAN, IPR and ALA potentiated guanfacine induced hypothermia. Repetitive DMI, AMI and MAP treatment attenuated clonidine-induced hypothermia whereas guanfacine-induced hypothermia was potentiated by chronic treatment with DMI, AMI, MAP and MIAN, ECT applied without anaesthesia attenuated both clonidine and guanfacine hypothermia, however, under ethyl ether anaesthesia ECT was effective only towards guanfacine hypothermia. This discrepancy is discussed in terms of the relative selectivity of the agonists used, the reliability of agonist studies for indexing receptor function, and possible pharmacokinetic interaction.

Limits to chemotherapy of depression.

A large number of depressed patients are undiagnosed and therefore untreated. A substantial proportion of those patients who are treated are allegedly 'refractory', 'resistant' or 'non-responsive' to anti-depressant drug therapy. Definitions and criteria for the use of these terms vary, or are totally lacking, and incidence figures in the literature vary between 10 to 50%. In addition, 3 to 15% of depressed patients otherwise satisfactorily treated suffer unwanted effects. Such observations clearly illustrate limits to successful antidepressive therapy. Some of these may require new approaches on the part of medical education or further research and development of psycho-active drugs on existing lines. However, the limitations imposed by the unwanted effects of antidepressives are more tangible and might be substantially influenced when manufacturers actively and succinctly inform the medical profession about changes in the ADR profiles of their products. As an example, the evolution of the ADR profile of the antidepressant maprotiline is demonstrated: the frequency of reports on convulsions in association with maprotiline treatment in the USA and the UK decreased about four-fold and seven-fold respectively after appropriate adjustments of daily-dose ranges were recommended.