Autoradiographic demonstration of increased serotonin 5-HT2 and beta-adrenergic receptor binding sites in the brain of suicide victims

Suicidal behavior has been linked to a deficiency in serotonin neurotransmission, but it is not known which brain regions are involved. We determined the pattern of alteration in serotonin 5-HT2 (5-HT2) receptor binding sites in suicide victims in prefrontal cortex compared with temporal cortex using a matched-pairs design to study 11 suicide victims and 11 matched controls, by both membrane binding and quantitative receptor autoradiography. Since a relationship between the serotonergic and noradrenergic systems has been proposed, we also examined beta-adrenergic receptor binding sites. Binding to 5-HT2 and beta-adrenergic sites in slide-mounted sections correlated strongly with binding site number in membrane preparations. A specific laminar distribution of 5-HT2 binding sites was found in both the control and suicide groups, whereas beta-adrenergic binding sites did not differ across cortical layers. A significant increase was found in suicide victims across all cortical layers in both receptor subpopulations in the prefrontal cortex, but only beta-adrenergic sites were increased in the temporal cortex. We conclude that suicide is associated with a localized increase in 5-HT2 binding sites.

Acute effects of single and repeated electroconvulsive therapy on plasma catecholamines and blood pressure in major depressive disorder

The role of activation of adrenergic neurons by electroconvulsive therapy (ECT) in its antidepressant action was studied by examining acute sympathetic nervous system (SNS) responses to ECT during a course of treatment in patients with melancholia. ECT had an acute dose-dependent effect on plasma norepinephrine (NE) level and blood pressure. The postictal increase in plasma NE and blood pressure was independent of electrical seizure duration. Acute levels of NE and epinephrine after ECT correlated positively with ECT dosage. No cumulative effect of repeated ECT was found on the SNS responses. ECT does activate the SNS in a dose-dependent fashion. However, alternative strategies seem necessary for studying the action of ECT on noradrenergic neurons to identify effects that are cumulative, correspond more closely to the time course of its antidepressant action, and correlate with clinical outcome.

Serotonin and suicidal behavior

Studies of the brain of suicide victims indicate there is a decrease in brain stem levels of 5-HT and/or 5-HIAA. There also appears to be a region-specific increase in 5-HT2 receptors, which are post synaptic and may therefore be increased in number secondary to decreased serotonin levels. Lack of information about how 5-HT2 and other serotonin receptor populations are regulated hamper our ability to explain the mechanisms underlying these findings. If the initial reports of a decrease in the number of imipramine binding sites prove to be correct then this finding would be further evidence for an effect involving the serotonin neurons, seen in this case at the level of the terminals. The relationship between suicide attempters and completers remains to be worked out. However, studies of suicide attempters, particularly those making more lethal attempts, appear to confirm the findings made in the brain of suicide completers. Neuroendocrine and CSF studies indicate the presence of serotonin subresponsivity and lower levels of CSF 5-HIAA. Thus, the overall direction of change is towards a weaker serotonin signal which rather than being due to a primary receptor defect (a possibility that cannot be ruled out but for which there is no current evidence), appears to be due to reduced levels of serotonin release. The causes of this effect represent a research challenge. It is clear that reduced levels of serotonin alone cannot explain the timing and type of suicidal behavior. Future studies must address the role of other neurotransmitters which may explain why some aggression is directed outward (towards other people) and in other cases the aggression is directed toward the self (suicidal behavior). Defining the role of serotonin and other involved transmitter systems is a necessary step before a comprehensive pharmacological treatment plan can be designed and tested.

Amoxapine versus amitriptyline for continuation therapy of depression

The efficacy of continuation therapy with tricyclic antidepressants has been established in a number of controlled trials. This study investigated the efficacy of continuation therapy with a relatively new antidepressant, amoxapine, using a double-blind controlled comparison with amitriptyline. Subjects met DSM-III criteria for major depressive disorder and were randomized to treatment with either amoxapine 400 mg (N = 47) or amitriptyline 300 mg (N = 45). The acute phase lasted up to 8 weeks. Responders were continued on the same drug at the same dose for a 16-week continuation phase. Some measures found more rapid onset for amitriptyline, which is inconsistent with findings from some prior studies. Amitriptyline was more effective in inducing full recovery. There was a trend for higher relapse rates on amoxapine, perhaps related to the fact that there were more partial responders entering continuation therapy from this group. Side effect rates were equivalent in the two drugs. However, physicians rated amoxapine's side effects as more frequently interfering with its therapeutic effect. These data suggest that amoxapine does not offer any clear advantage over amitriptyline for continuation therapy in patients who have major depressive disorder. Of potential clinical relevance is the finding that achieving full recovery in the acute phase may reduce the likelihood of relapse in the continuation phase, regardless of the type of antidepressant medication prescribed.

CSF 5-HIAA and HVA concentrations in elderly depressed patients who attempted suicide

CSF findings distinguished 12 elderly depressed patients who attempted suicide from nine depressed patients who did not and from seven normal control subjects. Psychosocial factors and measures of psychopathology did not differentiate suicidal from nonsuicidal patients. Biochemical factors may be important in evaluating suicide risk in the elderly.

Effects of age and gender on CNS serotonergic responsivity in normal adults

The effects of age and gender on central nervous system (CNS) serotonergic responsivity were assessed with a neuroendocrine challenge test in 30 normal adults. Subjects greater than or equal to 30 years of age, compared with younger subjects, exhibited decreased prolactin secretion in response to a 60-mg oral dose of dl-fenfluramine hydrochloride, an indirect serotonin agonist. Furthermore, women had greater prolactin responses than men. As prolactin secretory capacity appears to be stable through midlife, the age-associated decrease in fenfluramine-induced prolactin release suggests a decline in CNS serotonergic responsivity. In contrast, the finding of greater prolactin release in women than in men probably reflects the effects of nonserotonergic modulatory influences at the level of the lactotroph. Age and gender effects must be considered in studies of the CNS serotonergic system.

Demonstration of high- and low-affinity beta-adrenergic receptors in slide-mounted sections of rat and human brain

Studies using isolated cell membranes have shown that beta-adrenergic receptors exist in two interconvertible conformations, one with high affinity for agonists and the other with low affinity. Guanine nucleotides and sodium shift high-affinity receptor sites into low-affinity sites. We sought to demonstrate affinity states of the beta-adrenergic receptor in slide-mounted sections of rat and human postmortem brain, and to determine using quantitative receptor autoradiography the regional distribution in the brain of high-affinity receptors relative to the total population of beta-adrenergic receptors. The beta-adrenergic agonist isoproterenol inhibited the binding of 125I-iodopindolol to slide-mounted sections of rat forebrain and human premotor cortex in a biphasic manner. Approximately 80% of the beta-receptor sites in both rat and human brain showed high-affinity for isoproterenol (7-14 nM). Treatment with 0.1 mM non-hydrolyzable guanine nucleotide 5'-guanylylimidodiphosphate and 25 mM NaCl abolished high-affinity binding in rat brain sections and reduced it in human brain sections. These findings were confirmed by membrane studies using similar tissue samples. For autoradiographic studies, 17 nM isoproterenol displaced 71% of the high-affinity sites without affecting low-affinity beta-adrenergic receptors. Digital subtraction was used to selectively visualize beta-receptors in the high-affinity conformation. The proportion of beta-adrenergic receptors in the high-affinity conformation differed significantly across rat brain regions and across human cortical layers. We conclude that beta-adrenergic affinity states, presumably reflecting the interaction of the receptor with a G-protein, occur in slide-mounted sections of rat brain and persist in human postmortem material.(ABSTRACT TRUNCATED AT 250 WORDS)

Normalization of blunted lymphocyte beta-adrenergic responsivity in melancholic inpatients by a course of electroconvulsive therapy

Electroconvulsive therapy has been reported to desensitize brain beta-adrenergic receptors in rodents, but this effect has not been studied in man. We examined the effect of a course of electroconvulsive therapy on lymphocyte beta-adrenergic responsivity in 19 inpatients with melancholia. Before treatment, beta-adrenergic cyclic adenosine monophosphate response to isoproterenol was significantly blunted in the patients compared with controls. Following a course of electroconvulsive therapy, beta-adrenergic responsivity increased such that patients no longer differed from controls. Thus, blunted lymphocyte beta-adrenergic responsivity is a state-dependent effect of melancholia that can be corrected by a therapeutic course of electroconvulsive therapy. The effect of electroconvulsive therapy on this beta-adrenergic system is in the opposite direction to that reported for rodent forebrain, where electroconvulsive therapy causes desensitization, and may reflect differences between peripheral and central effects, species differences, or disease effects.

Prevalence of recent cocaine use among motor vehicle fatalities in New York City

We determined the prevalence of recent cocaine and alcohol use among motor vehicle fatalities occurring in New York, NY, from 1984 through 1987. Recent cocaine use was detected at autopsy in 18.2% of the sample and no significant difference between drivers (20.0%) and passengers (13.9%) was found. Both alcohol and cocaine metabolites were found in 10.0% of cases tested. The prevalence of cocaine metabolites or alcohol detected in driver fatalities aged 16 through 45 years did not change significantly when the period prior to the widespread availability of "crack" cocaine (1984 through 1985) was compared with the period immediately following the introduction of crack cocaine (1986 through 1987). Additional studies are needed both to elucidate the association between cocaine use and these fatalities and to determine the value of screening persons seriously injured in traffic accidents in areas where such drug use is endemic.

Statistical issues in the identification of risk factors for suicidal behavior: the application of survival analysis

Studies of suicide risk factors generally examine suicidal behavior as a dichotomous outcome. Survival analytic techniques are discussed in which the time until a suicide attempt from a specific point, such as prior attempt or onset of illness, is also examined. These procedures can incorporate information on those lost to followup or "censored." One survival analytic technique, Cox's proportional hazards model, is a particularly informative statistical technique for the study of suicidal risk factors because several covariates can be incorporated. Illustrative analyses estimate the significance of different risk factors, and demonstrate that there is a 32% increase in the relative risk of a suicide attempt associated with each prior attempt.

Inhibition of serotonin-amplified human platelet aggregation by ketanserin, ritanserin, and the ergoline 5HT2 receptor antagonists-LY53857, sergolexole, and LY237733

Human platelets are known to possess 5HT2 receptors which, when activated, amplify the aggregation response produced by other aggregating agents. Several 5HT2 receptor antagonists, including ketanserin and ritanserin, are known to antagonize serotonin-mediated aggregation of human platelets. In the present study, we document the ability of three ergoline 5HT2 receptor antagonists, LY53857, sergolexole, and LY237733, to antagonize the serotonergic component of the human platelet aggregation response. Potencies of the ergoline esters (LY53857 and sergolexole) and the ergoline amide (LY237733) to inhibit serotonin-amplified platelet aggregation responses were similar to the potencies of ketanserin and ritanserin under the conditions of our study. Furthermore, all five 5HT2 receptor antagonists were capable of fully inhibiting the serotonergic component of the platelet aggregation response. In contrast to these potent ergoline esters and amides, 1-isopropyl dihydrolysergic acid (up to 10(-5)M), a putative metabolite of the ergoline esters, was ineffective under these in vitro conditions. These data are consistent with the high potency of these ergolines as antagonists of 5HT2 receptors and further support the involvement of 5HT2 receptors on human platelets in the amplifying response to serotonin.

Evidence for the 5-HT hypothesis of suicide. A review of post-mortem studies

Although suicide was traditionally considered an extreme response to stress, with the most frequent stress being depressive illness, severity of depression does not distinguish those who commit suicide from non-suicide attempters. A biological role involving the serotonergic system, possibly associated with a genetic risk factor, has been postulated. Low levels of 5-HT and 5-HIAA have been found in post-mortem examinations of brain-stem tissues of suicide victims (levels in cortical tissue were generally normal). An increased number of 5-HT2 receptors was found in the pre-frontal cortex of suicide victims, such upregulation having been demonstrated in induced 5-HT deficiency states; 5-HT1A receptors were also increased. Receptor populations may be altered by chronic psychotropic medication; e.g. 5-HT2 downregulation occurs following administration of antidepressants. There is some indication that the adrenergic system may be involved as well, but this will require further study. Antidepressant drugs may be effective in preventing suicide in patients with non-depressive syndromes who exhibit suicidal behaviour.

Is neuroleptic dysphoria a healthy response?

We examined the relationship between neuroleptic-induced extrapyramidal effects, subjective neuroleptic dysphoria, and clinical outcome in acutely psychotic inpatients. Thirteen of 50 consecutively admitted patients experienced severe neuroleptic dysphoria. Dysphoric patients were less likely to comply with neuroleptic, but nine did complete neuroleptic trials. The compliant dysphoric inpatients received significantly lower neuroleptic doses compared with nondysphoric patients, and yet had equivalent overall improvement of psychotic symptoms and less severe extrapyramidal effects. Despite having fewer physical signs of akinesia, dysphoric patients were significantly more distressed from akinesia than nondysphoric. We conclude that while some neuroleptic dysphoric patients become noncompliant, others benefit from dysphoria by negotiating for lower, less toxic, and yet effective neuroleptic dosages.

Prediction of response of chronic depression to imipramine

We had previously reported that imipramine was superior to placebo for the treatment of chronic depression. As a part of that study, we subsequently investigated clinical and demographic variables which might be associated with favorable or poor outcome for treatment with imipramine or placebo. Results are reported herein. Eight-six patients were entered and 53 completed an 8-week protocol. Outcome was assessed based on a 6-week, double-blind treatment phase, which followed a 2-week, single-blind placebo phase. Outcome was not found to significantly relate to demographic variables, severity or course of depression, diagnostic subtype, symptom profile, or DST results. Some modest associations were found between 'neurotic' personality traits and poor outcome. Results are discussed and compared with prior studies of prediction of tricyclic antidepressant response in both acute and chronic depressions.

Serotonergic responsivity in male young adults with autistic disorder. Results of a pilot study

Altered serotonergic function has been postulated to exist in autistic disorder. Central serotonergic responsivity was assessed with a neuroendocrine challenge test in seven male young adults with autistic disorder and in seven age- and gender-matched healthy controls. Binding indexes and physiologic responsivity of the platelet serotonin-2 (5-HT2) receptor complex were also measured, as was whole-blood serotonin content. Compared with controls, autistic subjects had substantially blunted prolactin release in response to a 60-mg oral dose of fenfluramine hydrochloride, an indirect serotonin agonist [corrected]. Furthermore, the magnitude of serotonin-amplified platelet aggregation, mediated by the platelet 5-HT2 receptor complex, was reduced in the autistic group, as was the mean number of platelet 5-HT2 receptor sites. Among autistic subjects, fenfluramine-induced prolactin release correlated positively with the serotonin-amplified platelet aggregation response and negatively with whole-blood serotonin content. The results of the present study are compatible with the hypothesis that central serotonergic responsivity is decreased in male autistic young adults. Correlations between central and peripheral serotonergic measures in autistic subjects suggest that systemic alterations in serotonergic function may occur in autism.

A controlled study of the antidepressant efficacy and side effects of (-)-deprenyl. A selective monoamine oxidase inhibitor

Monoamine oxidase (MAO) inhibitors are effective antidepressants whose use is limited because of unwanted side effects and the possibility of a tyramine-induced hypertensive crisis (cheese reaction). (-)-Deprenyl (the official nonproprietary name for this substance is selegiline), a selective MAO type B inhibitor, may be safer and have fewer side effects, but its antidepressant efficacy is uncertain. A double-blind placebo-controlled study was carried out in depressed outpatients who were treated with (-)-deprenyl in an MAO type B selective dose range and at a higher nonselective dose range. (-)-Deprenyl did not have a statistically significant antidepressant effect after three weeks of treatment at doses of 10 mg/d. However, after six weeks and at higher doses (averaging about 30 mg/d for the second three weeks), (-)-deprenyl was superior to placebo in antidepressant effect with a positive response rate of 50% vs 13.6% and with a 41% reduction in the Hamilton Depression Rating Scale mean score vs 10% in the placebo-treated group. No hypertensive crises were seen. The rate of occurrence of side effects with (-)-deprenyl was no greater than with placebo. It was concluded that (-)-deprenyl is an effective antidepressant in a dose range where it is distinguished by the absence of many of the side effects typical of nonselective MAO inhibitors.

Imipramine and social-vocational adjustment in chronic depression

The authors compared the effects of 6 weeks of imipramine treatment with 6 weeks of placebo treatment on social and vocational impairment in chronic depression. Imipramine was associated with significantly greater pre- to posttreatment improvement of social-vocational impairments in chronic depression, suggesting that these impairments may have represented affective symptoms rather than characterologic deficits.

Catecholaminergic neurons in the ventrolateral medulla and nucleus of the solitary tract in the human

Catecholaminergic neurons in the ventrolateral medulla (VLM) and nucleus of the solitary tract (NTS) are important because of their presumed roles in autonomic regulation, including the tonic and reflex control of arterial pressure, neuroendocrine functions, and the chemosensitivity associated with the ventral medullary surface. However, little is known about the connections of these neurons in the human brain. As a first step in analyzing the functional biochemical anatomy of catecholamine neurons in the human, we used antisera against tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) to localize medullary catecholamine-containing neurons and processes in the VLM and the NTS. Cells staining for TH were located throughout the VLM. Most cells staining for TH and PNMT, which are therefore adrenergic, occurred in an area of the VLM probably corresponding to the rostroventrolateral reticular nucleus. Axons of TH-immunoreactive neurons in the VLM projected (1) dorsally, in a series of parallel transtegmental trajectories, toward the dorsomedial reticular formation, the NTS, and vagal motor nucleus, (2) longitudinally, through the central tegmental field, as fascicles running parallel to the neuraxis, (3) ventrolaterally toward the ventral surface (VS) of the rostral VLM where they appeared to terminate, and (4) medially into the raphe, where they arborized. Similar systems of fibers were labeled for PNMT; the longitudinal bundles of PNMT-labeled axons were limited to the principal tegmental bundle and concentrated dorsally. Fibers containing PNMT were also identified in the medullary raphe, on the medullary ventral surface, and contacting intraparenchymal blood vessels. In the NTS, neurons exhibited immunoreactivity to both TH and PNMT: Four principal subgroups of TH-immunoreactive neurons were seen: a ventral, an intermediate, a medial, and a dorsal group. Perikarya containing PNMT were restricted to the dorsolateral aspect of the NTS. Processes containing TH and PNMT immunoreactivity were identified in the medial and dorsolateral NTS; others appeared to project between the NTS and the VLM and within the solitary tract. The presence of catecholaminergic fibers of the VLM interconnecting with the NTS, raphe, intraparenchymal microvessels, VS, and possibly the spinal cord suggests that the autonomic and chemoreceptor functions attributed to these neurons also may apply to the human.

Cognitive impairment in schizophrenia: specific relations to ventricular size and negative symptomatology

A number of studies of schizophrenia have demonstrated associations between cognitive impairment and both cerebral ventricle size and negative symptomatology. The nature of these associations, however, have been obscured by interstudy differences in the assessment of cognitive functioning and by the lack of function-related specificity in measures of structural brain abnormality. In this study, 28 SCID-diagnosed chronic schizophrenic inpatients were administered a brief comprehensive battery of neuropsychological tests, a computed tomography (CT) scan, and were rated for positive and negative symptomatology. Enlarged ventricle-to-brain ratio (VBR) of the anterior portion of the lateral ventricles, the frontal horns, was found to be related to deficits in general intellectual level, conceptual thinking, immediate verbal memory, and psychomotor speed. VBR of the more usually studied bodies of the lateral ventricles was associated only with deficits in verbal memory and motor speed. VBRs were unrelated to both positive and negative symptom measures in this sample. Results suggest that more widespread impairment of schizophrenics' cognitive functioning may be related to structural abnormality within the frontal lobes, complementing recent findings linking structural and metabolic abnormalities of this area of the brain to the disease itself.

Increased risk of suicide in persons with AIDS

The rate of suicide has been reported to be higher in persons with chronic and life-threatening illnesses (eg, cancer, Huntington's disease, and renal failure). We studied the rate of suicide in 1985 in New York City residents diagnosed with the acquired immunodeficiency syndrome (AIDS). There were 668 suicides in New York City residents in 1985, yielding a rate of 9.29 per 100,000 person-years. In men aged 20 to 59 years without a known diagnosis of AIDS, the rate was 18.75 per 100,000 person-years. There were 3828 individuals who lived with the diagnosis of AIDS for some part, or all, of 1985. There were 12 suicides in men aged 20 to 59 years from this group who lived 1763.25 person-years with a diagnosis of AIDS. This yields a suicide rate of 680.56 per 100,000 person-years. Thus, the relative risk of suicide in men with AIDS aged 20 to 59 years was 36.30 times (95% confidence limits, 20.45 to 64.42) that of men aged 20 to 59 years without this diagnosis, and 66.15 times (95% confidence limits, 37.38 to 117.06) that of the general population. We conclude that AIDS represents a significant risk factor for suicide.

Imipramine treatment for chronic depression

Antidepressant drugs in the treatment of chronic depressions have received little systematic study. We used a two-week, single-blind placebo washout followed by a six-week, double-blind comparison of imipramine hydrochloride and placebo in a sample of 76 outpatients with DSM-III dysthymic disorder entered into a trial at two centers. Subjects were preponderantly female, had insidious onset at an early age, and had depressions of moderate severity; 96% also met the DSM-III criteria for major depressive disorder at the time of presentation. Sixty percent had a history of persistent depressive symptoms sufficient to meet criteria for major depression for longer than two years. Markedly favorable responses occurred in 45% of imipramine-treated (n = 29) and 12% of placebo-treated (n = 25) patients and, respectively, 59% and 13% of those who completed the study. Imipramine produced significant advantage in measures of depressive symptoms, global severity of illness, and self-rated social and vocational function. Recovered patients experienced remission from both long-standing symptoms and deficits as well as more recently exacerbated aspects of their syndrome. Patients with pure dysthymic disorder of a mild, subsyndromal type were uncommon in these clinical settings. However, anti-depressant medication was effective for many moderately severe chronic depressions, which had previously been untreated or undertreated, presumably related to misdiagnosis.