Platelets as neuronal models in neuropsychiatric disorders.
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Blood Platelets↗
Biomedical subjects
R Weizman
Publications and source records attributed to R Weizman.
Peripheral benzodiazepine binding sites on platelet membranes are increased during diazepam treatment of anxious patients.
Reduced (24%) [3H]PK 11195 binding capacity to platelet membranes was observed in anxious patients in comparison to age- and sex-matched normal controls. Four weeks of diazepam treatment induced elevation (69%) in the maximal number of binding sites, and 1 week of drug withdrawal resulted in a slight decrease (16%) in 'peripheral' benzodiazepine binding sites as compared to their level during treatment.
Adult↗
Effects of acute and chronic methylphenidate administration on beta-endorphin, growth hormone, prolactin and cortisol in children with attention deficit disorder and hyperactivity.
The effect of 5 mg/p.o. methylphenidate (MPH) challenge on beta-endorphin (beta-EP), growth hormone (GH), prolactin (Prl) and cortisol was investigated in 16 children suffering from attention deficit disorder with hyperactivity (ADDH) before and after 4 weeks MPH treatment. The study population consisted of 13 males and 3 females aged 6-11 years. All patients were drug free for at least 3 months prior to investigation. The severity of ADDH symptomatology and response to MPH chronic treatment was assessed using parent/teacher abbreviated Conners rating scale. Blood samples for beta-EP, cortisol, Prl and GH were drawn before initiation of treatment (basal pre-treatment level), 2 hours after MPH challenge, 4 weeks after MPH treatment (basal post-treatment level) and 2 hours after re-challenge with MPH. Chronic MPH treatment resulted in a decrease in basal Prl levels (5.5 +/- 2.8 vs 3.7 +/- 1.9 ng/ml; p less than 0.05). Pre-treatment challenge stimulates significantly both beta-EP (15.0 +/- 7.5 vs 12.5 +/- 5.3 pmol/l; p less than 0.05) and cortisol secretion (20.6 +/- 6.6 vs 12.6 +/- 5.8 micrograms/dl; p less than 0.05), and suppressed Prl secretion (4.0 +/- 1.5 vs 5.5 +/- 2.8 ng/ml; p less than 0.05). Re-challenge with MPH enhanced beta-EP levels (14.9 +/- 8.6 vs 10.6 +/- 5.0 pmol/l; p less than 0.05) but failed to affect cortisol, Prl and GH secretion. The acute and chronic neuroendocrine effects of MPH administration might be related to its dopaminergic and adrenergic agonistic activity. It might be that the stimulatory effect of single and repeated acute MPH administration on beta-EP release contributes to the beneficial effect of MPH treatment in ADDH children.
Attention Deficit Disorder with Hyperactivity↗
Sexual behavior in healthy married elderly men.
Sexual behavior was evaluated in 81 men aged 60-71 years (34 men aged 60-65 years and 47 men aged 66-71 years). All subjects were married, physically healthy, and with no psychopathology or marital problems. Sexual function was evaluated by a self-report three-point rating scale. Thirty-six percent of the whole study population reported impotence, with no significant difference between the two age groups. About half of the total population reported regular masturbatory activity. A decline in frequency of sexual intercourse and an increase in frequency of masturbation in subjects aged 66-71 years as compared to subjects aged 60-65 indicates that the interest in sexuality continues in elderly men although the form of sexual expression changes from active sexual intercourse to a self-pleasuring/autoerotic form. Evaluation of sexual activity in advanced age is recommended and appropriate therapy in case of sexual dysfunction should be offered to elderly men.
Aged↗
Lack of effect of 28 days of neuroleptic treatment on platelet benzodiazepine binding sites in schizophrenics.
Twenty-eight days of neuroleptic treatment of 11 schizophrenics aged 16-23 years did not affect the binding values of 3H-PK 11195 to platelets. This lack of effect was in contrast to reduced peripheral benzodiazepine binding sites (PBS) observed in platelets of schizophrenics medicated over 2 years. These results may indicate that neuroleptic-induced down-regulation of PBS is a time-dependent phenomenon.
Adolescent↗
Peripheral-type benzodiazepine-binding sites in platelets of schizophrenics with and without tardive dyskinesia.
The density of peripheral-type benzodiazepine (BZ)-binding sites was studied in platelets of 10 medicated chronic schizophrenics with tardive dyskinesia (TD), 10 medicated chronic schizophrenics without TD, 7 drug-free schizophrenics, and 10 normal controls. The age range of the study population was 36-60 years. Age and sex distribution were similar in all 4 groups. The unmedicated schizophrenics did not differ in their maximal binding capacity from the healthy controls. A significant decrease in the density of peripheral-type BZ-binding sites in platelets was observed in treated schizophrenics both with and without TD in comparison to controls and untreated schizophrenics. The reduction in [3H]PK 11195 binding was more pronounced in TD patients (31.3% of controls) than in patients without TD (21.1% of controls). However, this parameter failed to discriminate statistically between TD and non-TD medicated schizophrenics.
Adult↗
High affinity [3H]imipramine binding and serotonin uptake to platelets of adolescent females suffering from anorexia nervosa.
High affinity [3H]imipramine binding and [3H]serotonin uptake to platelets were investigated in 17 anorexic females aged 15-18 years as compared to 15 healthy females of similar ages. A significant decrease in the density of [3H]imipramine binding sites was observed in anorexics as compared to controls (368 +/- 40 vs 517 +/- 38 fmoles/mg protein, p less than 0.01). No alteration in Kd values or in the kinetic parameters of serotonin uptake (Vmax, Km) were noted. The fact that the decrease in imipramine binding is not accompanied by a parallel reduction in serotonin uptake might indicate that anorexia nervosa is not ultimately related to major depression and that the imipramine binding site is not identical to the serotonin uptake site.
Adolescent↗
Reduced 3H-imipramine binding but unaltered 3H-serotonin uptake in platelets of adolescent enuretics.
High affinity 3H-imipramine binding and 3H-serotonin uptake to platelets was evaluated in nine untreated adolescent enuretics (ages 13-18) and nine age- and sex-matched controls. A significant decrease in the maximal binding of 3H-imipramine (Bmax) was observed in the enuretics as compared to the controls. No alteration in the affinity of 3H-imipramine to its binding sites (Kd) or in serotonin uptake kinetic parameters (Vmax, Km) was detected. The lack of correlation between Bmax and Vmax values might indicate that the binding sites for imipramine and the sites for serotonin uptake are not identical.
Adolescent↗
Humoral-endorphin blood levels in autistic, schizophrenic and healthy subjects.
Basal morning humoral (H)-endorphin blood levels were assessed in ten autistic patients, 12 chronic schizophrenic patients and 11 healthy control subjects. Four autistic patients and four schizophrenic patients were drug free for at least 6 months while all other psychiatric patients were under treatment with antidopaminergic agents. Significantly reduced opioid levels were observed in the autistic group (827 +/- 103 vs 1121 +/- 75 pg-eq/ml, P less than 0.025), although the difference was actually only 26% of the control mean. A similar tendency toward low H-endorphin levels was also observed in the schizophrenic patients; however this difference was not significant (919 +/- 129 vs 1121 +/- 75 pg-eq/ml; NS). No significant difference was obtained between subjects suffering from the two psychiatric disorders (827 +/- 103 vs 919 +/- 129 pg-eq/ml; NS). Various interpretations of the decreased secretion of H-endorphin are discussed.
Adolescent↗
High-affinity 3H-imipramine binding in platelets of children and adolescents with major affective disorders.
High-affinity 3H-imipramine binding to platelet membranes was evaluated in 12 untreated children and adolescents aged 11-17 years who met the DSM-III criteria for major affective disorders. The affective patients were compared to 13 nonaffective subjects and 15 normal controls of similar ages. No significant difference in the maximal binding of 3H-imipramine (Bmax) and Kd values could be found among the three groups. 3H-Imipramine binding values failed to discriminate between patients with major depression and those with bipolar disorder, depressed type. No association between a positive family history of major affective disorders and 3H-imipramine binding values was detected.
Adolescent↗
Basal plasma HGH and cortisol levels and the effect of clonidine administration in female migrainous patients.
Clonidine, a central alpha-adrenergic agent and prophylactic antimigraine drug is known to stimulate human growth hormone (HGH) release and to suppress cortisol secretion. A possible association between basal hormonal levels and response to either acute clonidine test or chronic treatment in female migrainous patients was investigated. 15 females, aged 18-43 years, suffering from migraine, underwent an acute clonidine test by administration of a single oral dose of 0.15 mg. High basal HGH levels (greater than or equal to 9 ng/ml) were observed in 6 patients, while the other 9 patients demonstrated normal low basal HGH levels. Acute clonidine administration induced a marked rise of HGH in 8 of the 9 patients with low basal HGH. In 4 of the 8 responders HGH levels exceeded 20 ng/ml and 3 subjects reached the acromegalic range (greater than 90 ng/ml). The mean response in this group was higher than in a reference group consisting of children and adolescents. It is suggested that the basal hypersecretion and the hyperresponsiveness of HGH to clonidine provocation test in some migrainous patients results from a hypersensitivity of the central alpha-adrenergic receptors. 12 of the 15 females were treated for 10 weeks with clonidine at gradually increased doses of 0.05 mg/day up to a maximal dose of 0.15 mg/day. A marked suppressive effect on cortisol secretion was observed in the migrainous patients after acute and chronic administration of clonidine. No correlation was observed between HGH and cortisol response to acute or chronic clonidine administration and the prophylactic effect of clonidine on migraine.
Adolescent↗
Sexual dysfunction associated with hyperprolactinemia in males and females undergoing hemodialysis.
Fifty-nine uremic patients (38 males and 21 females) maintained on chronic hemodialysis (CHD) served as the subjects in a study of the relationship between sexual dysfunction and serum prolactin levels (SPL). Sexual desire and activity were evaluated by a self-report sexual function rating scale (SFRS). About half the population of this study reported sexual dysfunction. Males and females reporting disturbance of sexual function had significantly higher SPL than those with normal sexual function. Bromocriptine treatment in five hyperprolactinemic patients reduced SPL to normal range and improved the sexual function. Association between sexual dysfunction and hyperprolactinemia in uremic patients is suggested.
Adult↗
The correlation of increased serum prolactin levels with decreased sexual desire and activity in elderly men.
Serum prolactin levels and sexual function were evaluated in 28 men from 60 to 64 years of age and in 44 men from 65 to 70 years of age. All subjects were married, physically healthy, and had no psychopathology or marital problem. About a third of the men aged 60 to 70 years suffered from impotence. No obvious correlation between elevated levels of serum prolactin and impotence was obtained. Subjects aged 65 to 70 who had decreased libido exhibited a significant elevation of serum prolactin levels, while subjects of the same age group who had reserved (normal) libido appeared to have low serum prolactin levels. Nine of ten men aged 60 to 70 years with serum prolactin levels above 40 ng/ml reported decreased libido. Potent men of both age groups (60-70 years) with high prolactin levels showed a tendency to have a decrease in frequency of sexual intercourse. Thus, it seems that mild hyperprolactinemia in aging men may be associated with decreased sexual desire and frequency of sexual activity.
Aged↗
Dopamine receptors in a rat model of minimal brain dysfunction.
A model of minimal brain dysfunction (MBD) in rats based on injection of 6-OH-dopamine (DA) intracisternally on the 5th day of life has been described previously. Since 6-OH-DA pretreatment has been reported in adult rats to lead to a compensatory rise in DA receptor number, we measured DA receptor number in animals treated with 6-OH-DA on the 5th day of life, after completion of behavioral observations on days 17, 20 and 23 of life. Rats pretreated with 6-OH-DA at day 5 were found, on sacrifice on day 23, to have a mean increase of about 20% in caudate spiperone binding. There was a significant correlation between spiperone binding and gross activity in 6-OH-DA-treated animals but not in untreated animals. Since the significant correlation between receptor number and gross activity is negative and DA receptor stimulators are known to increase activity, it appears that receptor number changes are not directly related to hyperactivity.
Aging↗
Abnormal immune response to brain tissue antigen in the syndrome of autism.
Cell-mediated immune response to human myelin basic protein was studied by the macrophage migration inhibition factor test in 17 autistic patients and a control group of 11 patients suffering from other mental diseases included in the differential diagnosis of the syndrome of autism. Of the 17 autistic patients, 13 demonstrated inhibition of macrophage migration, whereas none of the nonautistic patients showed such a response. The results indicate the existence of a cell-mediated immune response to brain tissue in the syndrome of autism.
Adolescent↗
Abnormal growth hormone response to TRH in chronic adolescent schizophrenic patients.
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Adolescent↗
Anorexia nervosa associated with hormonal replacement therapy in an adolescent gonadal dysgenesis.
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Adolescent↗
[Minimal brain dysfunction--a critical review].
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Attention Deficit Disorder with Hyperactivity↗