Nimodipine increases CSF somatostatin in affectively ill patients

Differential serum levels of CACNA1C, circadian rhythm and stress response molecules in subjects with bipolar disorder: Associations with genetic and clinical factors

BACKGROUND

Many patients with bipolar disorder (BD) do not respond to or have difficulties tolerating lithium and/or other mood stabilizing agents. There is a need for personalized treatments based on biomarkers in guiding treatment options. The calcium voltage-gated channel CACNA1C is a promising candidate for developing personalized treatments. CACNA1C is implicated in BD by genome-wide association studies and several lines of evidence suggest that targeting L-type calcium channels could be an effective treatment strategy. However, before such individualized treatments can be pursued, biomarkers predicting treatment response need to be developed.

METHODS

As a first step in testing the hypothesis that CACNA1C genotype is associated with serum levels of CACNA1C, we conducted ELISA measures on serum samples from 100 subjects with BD and 100 control subjects.

RESULTS

We observed significantly higher CACNA1C (p < 0.01) protein levels in subjects with BD. The risk single nucleotide polymorpshism (SNP) (rs11062170) showed functional significance as subjects homozygous for the risk allele (CC) had significantly greater CACNA1C protein levels compared to subjects with one (p = 0.013) or no copies (p = 0.009). We observed higher somatostatin (SST) (p < 0.003) protein levels and lower levels of the clock protein aryl hydrocarbon receptor nuclear translocator-like (ARTNL) (p < 0.03) and stress signaling factor corticotrophin releasing hormone (CRH) (p < 0.001) in BD. SST and period 2 (PER2) protein levels were associated with both alcohol dependence and lithium response.

CONCLUSIONS

Our findings represent the first evidence for increased serum levels of CACNA1C in BD. Along with altered levels of SST, ARNTL, and CRH our findings suggest CACNA1C is associated with circadian rhythm and stress response disturbances in BD.

Antidepressant-like activity of liposomal formulation containing nimodipine treatment in the tail suspension test, forced swim test and MAOB activity in mice

Previous studies have shown that intracellular calcium ion dysfunction may be an etiological factor in affective illness. Nimodipine (NMD) is a Ca(2+) channel blocker that has been extensively investigated for therapy of central nervous system (CNS) disorders. In this work, we have evaluated the antidepressant-like activity of nimodipine encapsulated into liposomes (NMD-Lipo) in mice through tail suspension and forced swim assays, as well as MAOB activity. During the tail suspension test, the administration of NMD-Lipo at 0.1, 1 and 10mg/kg was able to promote a reduction in the immobility time of animals greater than the positive control (imipramine). In the forced swim test, the immobility time of mice treated with NMD-Lipo was reduced. This reduction was significantly greater than that found in the animals treated with imipramine and paroxetine. This may suggest that NMD-Lipo provides more antidepressant-like activity than in positive controls. The groups that received a combination of liposomal NMD and antidepressant drugs showed lower immobility time than the groups, which were treated only with imipramine or paroxetine. The mice treated with the combination of NMD-Lipo and reserpine presented an increase in the time of immobility compared with animals treated only with NMD-Lipo. There was a significant decrease in MAOB activity in animals treated with NMD-Lipo compared with untreated animals. The results of the tail suspension test, forced swim test and MAOB activity suggested that the antidepressant activity of NMD-Lipo may be related to an increase in the cerebral monoamine concentrations.

Decreasing procedural pain over time of left prefrontal rTMS for depression: initial results from the open-label phase of a multi-site trial (OPT-TMS)

BACKGROUND

There is much interest in whether daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) over several weeks may become a clinically useful antidepressant treatment. Although rTMS appears largely safe, many patients report that this procedure is somewhat painful, which may restrict its ultimate appeal and utility. We analyzed interim results from the open-label phase of a multi-site randomized trial of rTMS as a treatment for depression to investigate whether the procedural pain of left prefrontal rTMS changes over time.

METHODS

Patients with unipolar depression who had failed to respond during at least three weeks of the sham-controlled double-masked rTMS were then offered three more weeks (15 sessions) of open-label rTMS. Retrospective pain ratings and state emotional factors from 20 subjects were assessed using visual analog scales (VAS) recorded on computers before and after each treatment (289 sessions).

RESULTS

Over the 15 treatment sessions, subjective reports of the painfulness of rTMS decreased 48% from baseline. This reduction, although greatest in the first few days, continued steadily (average 2.11 points per session) over the 3 weeks of treatment. The analysis found a significant effect for rTMS-session (p<0.0001) on rTMS-procedural pain over and above changes in subjective emotional states.

CONCLUSION

The procedural pain of left, prefrontal rTMS decreases over time, apparently independently of other emotional changes. Since rTMS scalp pain may decline over time, physicians and patients may decide to continue treatment despite initial discomfort. These observational data can be better tested once the data from the blinded phase of the trial becomes available.

Antidepressants influence somatostatin levels and receptor pharmacology in brain

This study investigated how the administration (acute and chronic) of the antidepressants citalopram and desmethylimipramine (DMI) influences somatostatin (somatotropin release inhibitory factor, SRIF) levels and SRIF receptor density (sst(1-5)) in rat brain. Animals received either of the following treatments: (1) saline for 21 days (control group), (2) saline for 20 days and citalopram or DMI for 1 day (citalopram or DMI acute groups), (3) citalopram or DMI for 21 days (citalopram or DMI chronic groups). Somatostatin levels were determined by radioimmunoassay. [(125)I]LTT SRIF-28 binding in the absence (labeling of sst(1-5)) or presence of 3 nM MK678 (labeling of sst(1/4)) and [(125)I]Tyr(3) octreotide (labeling of sst(2/5)) binding with subsequent autoradiography was performed in brains of rats treated with both antidepressants. Somatostatin levels were increased after citalopram, but not DMI administration, in the caudate-putamen, hippocampus, nucleus accumbens, and prefrontal cortex. Autoradiography studies illustrated a significant decrease in receptor density in the superficial and deep layers of frontal cortex (sst(2)), as well as a significant increase in the CA1 (sst(1/4)) hippocampal field in brains of chronically citalopram-treated animals. DMI administration increased sst(1/4) receptors levels in the CA1 hippocampal region. These results suggest that citalopram and to a lesser extent DMI influence the function of the somatostatin system in brain regions involved in the emotional, motivational, and cognitive aspects of behavior.

Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes

Bipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology to determine the expression of approximately 22,000 mRNA transcripts in post-mortem tissue from two brain regions in patients with bipolar disorder and matched healthy controls. Dorsolateral prefrontal cortex tissue from a cohort of 70 subjects and orbitofrontal cortex tissue from a separate cohort of 30 subjects was investigated. The final analysis included 30 bipolar and 31 control subjects for the dorsolateral prefrontal cortex and 10 bipolar and 11 control subjects for the orbitofrontal cortex. Differences between disease and control groups were identified using a rigorous statistical analysis with correction for confounding variables and multiple testing. In the orbitofrontal cortex, 393 differentially expressed transcripts were identified by microarray analysis and a representative subset was validated by quantitative real-time PCR. Pathway analysis revealed significant upregulation of genes involved in G-protein coupled receptor signalling and response to stimulus (in particular the immune response), while genes relating to the ubiquitin cycle and intracellular transport showed coordinated downregulation in bipolar disorder. Additionally, several genes involved in synaptic function were significantly downregulated in bipolar disorder. No significant changes in gene expression were observed in the dorsolateral prefrontal cortex using microarray analysis or quantitative real-time PCR. Our findings implicate the orbitofrontal cortex as a region prominently involved in bipolar disorder and indicate that diverse processes are affected. Overall, our results suggest that dysregulation of the ubiquitin pathway and synaptic function may be central to the disease process.

Dihydropiridines mechanism of action in striatal isolated nerve endings: comparison with omega-agatoxin IVA

The relative contribution of Ca2+ and Na+ channels to the mechanism underlying the action of the dihydropiridines (DHPs), nimodipine, nitrendipine and nifedipine was investigated in rat striatum synaptosomes. The rise in internal Ca2+ (Ca(i), as determined with fura-2) induced by high K+ was unchanged by the DHPs, which like tetrodotoxin (TTX) inhibited both the rise in internal Na+ (Na(i), as determined with the Na+ selective indicator dye, SBFI) and the rise in Ca(i) induced by veratridine. Nimodipine and nitrendipine were much more potent than nifedipine. Oppositely to TTX and to the DHPs, the P/Q type Ca2+ channel blocker, omega-agatoxin IVA did not inhibit the rise in Ca(i) induced by veratridine, but inhibited the rise in Ca(i) induced by high K+. Veratridine-evoked release of dopamine, GABA, Glu, and Asp (detected by HPLC) was inhibited by nimodipine, nitrendipine, and TTX, while high K+-evoked release was unchanged by the DHPs or TTX. It is concluded that the reduction in presynaptic Na+ channel permeability might contribute to the cerebral effects of DHPs.

Low CSF somatostatin associated with response to nimodipine in patents with affective illness

BACKGROUND

In patients with depression, treatment with nimodipine has been shown to increase cerebrospinal fluid (CSF) somatostatin (SRIF) and ameliorate baseline global cerebral hypometabolism. This study was conducted to assess whether a low baseline level of CSF SRIF was associated with response to nimodipine treatment.

METHODS

Twenty-one depressed patients underwent lumbar puncture for analysis of CSF somatostatin-like immunoreactivity (SRIF-LI) during a medication-free period and after at least 6 weeks of nimodipine monotherapy. Twenty-five healthy control subjects were utilized as a comparison group. Clinical improvement was assessed using the Clinical Global Impression Scale for Bipolar Illness.

RESULTS

As predicted, baseline CSF SRIF-LI was significantly lower in eventual nimodipine responders (33.1 +/- 2.8 pg/mol) compared to eventual nonresponders [41.9 +/- 2.6 pg/mL; t(19) = 1.98, p =.03, one-tailed].

CONCLUSIONS

Low baseline CSF somatostatin in depression may be associated with response to nimodipine, which in turn may be related to the ability of nimodipine to increase CSF somatostatin.

The Stanley Foundation Bipolar Network. I. Rationale and methods

BACKGROUND

The Stanley Foundation Bipolar Network (SFBN) was created to address the paucity of help studies in bipolar illness.

AIMS

To describe the rationale and methods of the SFBN.

METHOD

The SFBN includes five core sites and a number of affiliated sites that have adopted consistent methodology for continuous longitudinal monitoring of patients. Open and controlled studies are performed as patients' symptomatology dictates.

RESULTS

The reliability of SFBN raters and the validity of the rating instruments have been established. More than 500 patients are in continuous daily longitudinal follow-up. More than 125 have been randomised to one of three of the newer antidepressants (bupropion, sertraline and venlafaxine) as adjuncts in a study of mood stabilizers and 93 to omega-3 fatty acids. A number of open clinical case series have been published.

CONCLUSIONS

Well-characterised patients are followed in a detailed continuous longitudinal fashion in both opportunistic case series and double-blind, randomised controlled trials with reliable and validated measures.

The use of nimodipine in the treatment of mood disorders

Nimodipine, a dihydropyridine calcium entry blocker, has been shown to protect from neuronal damage due to ischemia by providing for increased postischemic perfusion. Further, it has also been demonstrated to have antiepileptic properties. These two properties--calcium channel blockade and anticonvulsant benefits have been applied with success to mood disorder treatment. Although found helpful nearly a decade ago for uncomplicated mania, nimodipine may have particular benefits for those diagnostic subclasses of bipolar disorder most resistant to therapy, e.g., ultra-rapid-cycling bipolars and brief recurrent depressions.

Baseline cerebral hypermetabolism associated with carbamazepine response, and hypometabolism with nimodipine response in mood disorders

BACKGROUND

Positron emission tomography (PET) studies have reported baseline (medication free) differences between mood disorder patients and healthy control subjects, but relatively little is known about relationships between baseline PET scans and treatment responses. Carbamazepine (CBZ) and to a more limited extent nimodipine (NIMO) seem useful in mood disorders. We explored whether baseline regional cerebral glucose metabolism (rCMRglu) could discriminate CBZ and NIMO responders from nonresponders and healthy control subjects.

METHODS

In refractory mood disorder patients, we examined relationships between responses to these drugs, assessed by Clinical Global Impression-Improvement scores, and baseline rCMRglu, determined with fluorine-18 deoxy-glucose and PET.

RESULTS

CBZ responders had baseline left insular hyper-metabolism compared to healthy control subjects and nonresponders, whereas nonresponders had widespread (including left insular) hypometabolism. Degree of CBZ response correlated with baseline paralimbic (including insula) and prefrontal hypermetabolism. In responders but not nonresponders, CBZ decreased widespread metabolism, with the degree of decrease in left insula correlating with response. In contrast, NIMO responders but not nonresponders had baseline widespread (including left insular) hypometabolism. Left prefrontal and left insular baseline hypometabolism, but not metabolic changes with treatment correlated with degree of NIMO response.

CONCLUSIONS

These data suggest that baseline anterior paralimbic and prefrontal hypermetabolism may be associated with CBZ response, and hypometabolism with NIMO response. Based on these preliminary data, further exploration of relationships between baseline PET scans and treatment responses is indicated.

Quality of life and calcium channel blockade with nifedipine GITS versus amlodipine in hypertensive patients in Spain. Gastrointestinal Therapeutic System

OBJECTIVE

Compliance with hypertension treatment is affected by treatment-related factors (complexity, side effects), efficacy and compound-specific effects that impact on quality of life. This study examined the differences in quality of life produced by two once-daily calcium channel blockers using different delivery systems: nifedipine gastrointestinal therapeutic system (GITS) and amlodipine.

DESIGN

This was a double-blind, double-dummy, randomized clinical trial comparing nifedipine GITS (30 mg) and amlodipine (5 mg) for 24 weeks following a placebo run-in. Clinical, laboratory evaluations and quality-of-life data were assessed at screening, baseline randomization and three times during active therapy.

SETTING

The study was conducted in 13 medical clinics in Spain.

PATIENTS

The sample comprised 430 screened and 356 randomized patients with mild to moderate hypertension (diastolic blood pressure 95-114 mmHg).

MAIN OUTCOME MEASURES

Change in systolic and diastolic blood pressure and in health-related quality of life were the main outcome measures.

RESULTS

There were no significant differences between active treatment groups in the blood pressure changes (systolic blood pressure: nifedipine GITS -15.5 mmHg; amlodipine -15.7 mmHg). Spontaneous adverse events consistent with calcium channel blockage were not different. The nifedipine GITS group improved in all quality-of-life measures except Sexual Symptom Distress and showed a significantly greater improvement than amlodipine in overall Quality of Life (P< 0.05), General Perceived Health (P < 0.026) and its subscale Vitality (P < 0.019). The amlodipine group declined in overall Quality of Life, General Perceived Health, Vitality and Sleep Disturbance, and significantly in Sexual Symptom Distress (P < 0.045). However, this group improved in self-reported Cognitive Functioning (P=0.036), Mental Acuity (P < 0.005) and Detachment/disorientation (P=0.01).

CONCLUSIONS

These results suggest compound-specific effects on quality of life that may be due to differences in the delivery system. Nifedipine GITS is short-acting (2 h half-life) and is delivered continuously over a 24 h period, while amlodipine has a half-life of 40 h, which may produce more sustained low-level effects. While a more beneficial profile was observed for nifedipine, amlodipine demonstrated potential positive effects on cognitive functioning.

Nimodipine monotherapy and carbamazepine augmentation in patients with refractory recurrent affective illness

Of 30 patients with treatment-refractory affective illness, 10 showed a moderate to marked response to blind nimodipine monotherapy compared with placebo on the Clinical Global Impressions Scale. Fourteen inadequately responsive patients (3 unipolar [UP], 11 bipolar [BP]) were treated with the blind addition of carbamazepine. Carbamazepine augmentation of nimodipine converted four (29%) of the partial responders to more robust responders. Patients who showed an excellent response to the nimodipine-carbamazepine combination included individual patients with patterns of rapid cycling, ultradian cycling, UP recurrent brief depression, and one with BP type II depression. When verapamil was blindly substituted for nimodipine, two BP patients failed to maintain improvement but responded again to nimodipine and remained well with a blind transition to another dihydropyridine L-type calcium channel blocker (CCB), isradipine. Mechanistic implications of the response to the dihydropyridine L-type CCB nimodipine alone and in combination with carbamazepine are discussed.