Pathological Complete Response Following Different Neoadjuvant Treatment Strategies for Locally Advanced Rectal Cancer: A Systematic Review and Meta-analysis.

BACKGROUND: Pathological complete response (pCR) following neoadjuvant treatment for locally advanced rectal cancer (LARC) is associated with better survival, less local recurrence, and less distant failure. Furthermore, pCR indicates that the rectum may have been preserved. This meta-analysis gives an overview of available neoadjuvant treatment strategies for LARC and analyzes how these perform in achieving pCR as compared with the standard of care. METHODS: Pubmed, Embase, and Cochrane Central bibliographic databases were searched. Randomized controlled trials in which patients received neoadjuvant treatment for MRI-staged nonmetastatic resectable LARC were included. The primary outcome was pCR, defined as ypT0N0. A meta-analysis of studies comparing an intervention with standard fluoropyrimidine-based chemoradiation (CRT) was performed. RESULTS: Of the 17 articles included in the systematic review, 11 were used for the meta-analysis. Addition of oxaliplatin to fluoropyrimidine-based CRT resulted in significantly more pCR compared with fluoropyrimidine-based CRT only (OR 1.46), but at the expense of more ≥ grade 3 toxicity. Other treatment strategies, including consolidation/induction chemotherapy and short-course radiotherapy (SCRT), did not improve pCR rates. None of the included trials reported a benefit in local control or OS. Five-year DFS was significantly worse after SCRT-delay compared with CRT (59% vs. 75.1%, HR 1.93). CONCLUSIONS: All included trials fail to deliver high-level evidence to show an improvement in pCR compared with standard fluoropyrimidine-based CRT. The addition of oxaliplatin might result in more pCR but at the expense of more toxicity. Furthermore, this benefit does not translate into less local recurrence or improved survival.

Risk factors for non-closure of an intended temporary defunctioning stoma after emergency resection of left-sided obstructive colon cancer.

PURPOSE: A substantial part (21-35%) of defunctioning stomas created during resection for colorectal cancer will never be reversed. Known risk factors for non-closure are age, peri- or postoperative complications, comorbidity, and tumor stage. However, studies performed to identify these risk factors mostly focus on rectal cancer and include both preoperative and postoperative factors. This study aims to identify preoperative risk factors for non-reversal of intended temporary stomas created during acute resection of left-sided obstructive colon cancer (LSOCC) with primary anastomosis. METHODS: All patients who underwent emergency resection for LSOCC with primary anastomosis and a defunctioning stoma between 2009 and 2016 were selected from the Dutch ColoRectal Audit, and additional data were collected in the local centers. Multivariable analysis was performed to identify independent preoperative factors for non-closure of the stoma. RESULTS: A total of 155 patients underwent acute resection for LSOCC with primary anastomosis and a defunctioning stoma. Of these, 51 patients (32.9%) did not have their stoma reversed after a median of 53 (range 7-104) months of follow-up. In multivariable analysis, hemoglobin < 7.5 mmol/L (odds ratio (OR) 4.79, 95% confidence interval (95% CI) 1.60-14.38, p = 0.005), estimated glomerular filtration rate (eGFR) ≤ 45 mL/min/1.73 m2 (OR 4.64, 95% CI 1.41-15.10, p = 0.011), and metastatic disease (OR 6.12, 95% CI 2.35-15.94, p < 0.001) revealed to be independent predictors of non-closure. CONCLUSIONS: Anemia, impaired renal function, and metastatic disease at presentation were found to be independent predictors for non-reversal of intended temporary stomas in patients who underwent acute resection for LSOCC. In patients who have an increased risk of non-reversal, the surgeon should consider a Hartmann's procedure.

Anatomy and Cell Biology of Autism Spectrum Disorder: Lessons from Human Genetics.

Until recently autism spectrum disorder (ASD) was regarded as a neurodevelopmental condition with unknown causes and pathogenesis. In the footsteps of the revolution of genome technologies and genetics, and with its high degree of heritability, ASD became the first neuropsychiatric disorder for which clues towards molecular and cellular pathogenesis were uncovered by genetic identification of susceptibility genes. Currently several hundreds of risk genes have been assigned, with a recurrence below 1% in the ASD population. The multitude and diversity of known ASD genes has extended the clinical notion that ASD comprises very heterogeneous conditions ranging from severe intellectual disabilities to mild high-functioning forms. The results of genetics have allowed to pinpoint a limited number of cellular and molecular processes likely involved in ASD including protein synthesis, signal transduction, transcription/chromatin remodelling and synaptic function all playing an essential role in the regulation of synaptic homeostasis during brain development. In this context, we highlight the role of protein synthesis as a key process in ASD pathogenesis as it might be central in synaptic deregulation and a potential target for intervention. These current insights should lead to a rational design of interventions in molecular and cellular pathways of ASD pathogenesis that may be applied to affected individuals in the future.

Prospective Dutch colorectal cancer cohort: an infrastructure for long-term observational, prognostic, predictive and (randomized) intervention research.

BACKGROUND: Systematic evaluation and validation of new prognostic and predictive markers, technologies and interventions for colorectal cancer (CRC) is crucial for optimizing patients' outcomes. With only 5-15% of patients participating in clinical trials, generalizability of results is poor. Moreover, current trials often lack the capacity for post-hoc subgroup analyses. For this purpose, a large observational cohort study, serving as a multiple trial and biobanking facility, was set up by the Dutch Colorectal Cancer Group (DCCG). METHODS/DESIGN: The Prospective Dutch ColoRectal Cancer cohort is a prospective multidisciplinary nationwide observational cohort study in the Netherlands (yearly CRC incidence of 15 500). All CRC patients (stage I-IV) are eligible for inclusion, and longitudinal clinical data are registered. Patients give separate consent for the collection of blood and tumor tissue, filling out questionnaires, and broad randomization for studies according to the innovative cohort multiple randomized controlled trial design (cmRCT), serving as an alternative study design for the classic RCT. Objectives of the study include: 1) systematically collected long-term clinical data, patient-reported outcomes and biomaterials from daily CRC practice; and 2) to facilitate future basic, translational and clinical research including interventional and cost-effectiveness studies for both national and international research groups with short inclusion periods, even for studies with stringent inclusion criteria. RESULTS: Seven months after initiation 650 patients have been enrolled, eight centers participate, 15 centers await IRB approval and nine embedded cohort- or cmRCT-designed studies are currently recruiting patients. CONCLUSION: This cohort provides a unique multidisciplinary data, biobank, and patient-reported outcomes collection initiative, serving as an infrastructure for various kinds of research aiming to improve treatment outcomes in CRC patients. This comprehensive design may serve as an example for other tumor types.

A double hit implicates DIAPH3 as an autism risk gene.

Recent studies have shown that more than 10% of autism cases are caused by de novo structural genomic rearrangements. Given that some heritable copy number variants (CNVs) have been observed in patients as well as in healthy controls, to date little attention has been paid to the potential function of these non-de novo CNVs in causing autism. A normally intelligent patient with autism, with non-affected parents, was identified with a maternally inherited 10 Mb deletion at 13q21.2. Sequencing of the genes within the deletion identified a paternally inherited nonsynonymous amino-acid substitution at position 614 of diaphanous homolog 3 (DIAPH3) (proline to threonine; Pro614Thr). This variant, present in a highly conserved domain, was not found in 328 healthy subjects. Experiments showed a transient expression of Diaph3 in the developing murine cerebral cortex, indicating it has a function in brain development. Transfection of Pro614Thr in murine fibroblasts showed a significant reduction in the number of induced filopodia in comparison to the wild-type gene. DIAPH3 is involved in cell migration, axon guidance and neuritogenesis, and is suggested to function downstream of SHANK3. Our findings strongly suggest DIAPH3 as a novel autism susceptibility gene. Moreover, this report of a 'double-hit' compound heterozygote for a large, maternally inherited, genomic deletion and a paternally inherited rare missense mutation shows that not only de novo genomic variants in patients should be taken seriously in further study but that inherited CNVs may also provide valuable information.

Most patients reported positively or neutrally of having served as controls in the trials within cohorts design.

OBJECTIVES: To evaluate patients' experience of having served as controls without a notification at the time of randomization in the context of the trial within cohorts (TwiCs) design. METHODS: Patients were asked for their opinion on having served as controls in TwiCs, before and after having been provided the trial results. Patients had provided broad consent to randomization at cohort entry and had served as controls in one of two TwiCs (an exercise program after breast cancer treatment or radiotherapy dose-escalation for rectal cancer). RESULTS: Two to 6 years after cohort entry, 15% (n = 16) of all patients remembered having provided broad consent to randomization. Before disclosure of trial results, 47% (n = 52) of patients thought positively, 45% (n = 50) neutrally, and 2% (n = 2) negatively of having served as controls in one of the two trials. Seventeen percent (n = 18) of patients were positive, 65% (n = 71) neutral, and 11% (n = 12) negative about not having been notified when serving as controls. The survey results were comparable after disclosure of trial results. CONCLUSIONS: These results support the use of the TwiCs design with the staged-informed consent procedure. Keeping patients engaged and aware of the consents provided might further improve patients' experience of serving as controls in TwiCs.

Impact of Dose-Escalated Chemoradiation on Quality of Life in Patients With Locally Advanced Rectal Cancer: 2-Year Follow-Up of the Randomized RECTAL-BOOST Trial.

PURPOSE: Dose-escalated chemoradiation (CRT) for locally advanced rectal cancer did not result in higher complete response rates but initiated more tumor regression in the randomized RECTAL-BOOST trial (Clinicaltrials.gov NCT01951521). This study compared patient reported outcomes between patients who received dose-escalated CRT (5 × 3 gray boost + CRT) or standard CRT for 2 years after randomization. METHODS AND MATERIALS: Patients with locally advanced rectal cancer who were participating in the RECTAL-BOOST trial filled out European Organisation for Research and Treatment of Cancer QLQ-C30 and CR29 questionnaires on quality of life (QoL) and symptoms at baseline, 3, 6, 12, 18, and 24 months after start of treatment. Between-group differences in functional QoL domains were estimated using a linear mixed-effects model and expressed as effect size (ES). Symptom scores were compared using Mann-Whitney U test. RESULTS: Patients treated with dose-escalated CRT (boost group, n = 51) experienced a significantly stronger decline in global health at 3 and 6 months (ES -0.4 and ES -0.4), physical functioning at 6 months (ES -1.1), role functioning at 3 and 6 months (ES -0.8 and ES -0.6), and social functioning at 6 months (ES -0.6), compared with patients treated with standard CRT (control group, n = 64). The boost group reported significantly more fatigue at 3 and 6 months (83% vs 66% respectively 89% vs 76%), pain at 3 and 6 months (67% vs 36% respectively 80% vs 44%), and diarrhea at 3 months (45% vs 29%) compared with the control group. From 12 months onwards, QoL and symptoms were similar between groups, apart from more blood/mucus in stool in the boost group. CONCLUSIONS: In patients with locally advanced rectal cancer, dose-escalated CRT resulted in a transient deterioration in global health, physical, role, and social functioning and more pain, fatigue and diarrhea at 3 and 6 months after start of treatment compared with standard CRT. From 12 months onwards, the effect of dose-escalated CRT on QoL largely resolved.

A major metabolite of arginine vasopressin in the brain is a highly potent neuropeptide.

A peptide that accumulated as the major product during the proteolysis of arginine vasopressin by rat brain synaptic membranes was isolated and its structure was shown to be the hexapeptide pGlu-Asn-Cys(Cys)-Pro-Arg-Gly-NH2. When administered intracerebroventricularly in extremely low doses, this vasopressin fragment and its desglycinamide derivative facilitated memory consolidation in a passive avoidance situation. These vasopressin metabolites, which are devoid of pressor activity, constitute highly potent neuropeptides with selective effects on memory and related processes; they are activated via proteolytic processing of vasopressin by brain peptidases.

DOC2 proteins in rat brain: complementary distribution and proposed function as vesicular adapter proteins in early stages of secretion.

DOC2 proteins constitute a novel protein family that may function in secretion and contain a double C2 domain. We have cloned and characterized two DOC2 isoforms in rat brain and studied their interactions with other proteins implicated in secretion. DOC2A was virtually brain specific, DOC2B ubiquitous. Within brain, the isoforms were expressed nonuniformly and complementary within neurons, not astroglia, and copurified with synaptic vesicles. Affinity purification, yeast two-hybrid analysis, and coimmunoprecipitation revealed that DOC2 binds munc18, a protein also implicated in secretion. The first DOC2 C2 domain and most of munc18 are involved in direct interactions. Munc18 may regulate formation of 'core complexes' during vesicle docking, by interacting with syntaxin. We show that DOC2 and syntaxin compete for munc18. Other core complex components shifted the equilibrium between syntaxin-munc18 versus DOC2-munc18. These data suggest that DOC2 proteins are vesicular adapter proteins regulating munc18-syntaxin complexes and herewith synaptic vesicle docking.

A second independent pathway for development of mesencephalic dopaminergic neurons requires Lmx1b.

We identified the LIM homeodomain transcription factor Lmx1b in the mesencephalic dopamine (mesDA) systems of embryos and adults. Analysis of spatiotemporal expression in Lmx1b null mutants and wild-type mice implicated a cascade involving Lmx1b in the early development of mesDA neurons. Although disruption of this cascade did not block induction of tyrosine hydroxylase (TH), a key enzyme in DA synthesis, or Nurr1, a nuclear hormone receptor, Lmx1b knockout mice failed to induce the mesDA-specific homeodomain gene Ptx3 in TH-positive neurons. Eventually, this small set of TH-positive neurons was lost during embryonic maturation. The data suggest that at least two molecular cascades operate during the specification of the mesDA system, one specifying neurotransmitter phenotype and another essential for other aspects of mesDA neuron differentiation.

Prophylaxis of radiation-induced nausea and vomiting: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: The aim of this article was to systematically review the efficacy and safety of various antiemetics in prophylaxis of radiation-induced nausea and vomiting (RINV). METHODS: A literature search of Ovid MEDLINE, EMBASE and Cochrane CENTRAL was performed to identify randomized controlled trials (RCTs) that evaluated the efficacy of prophylaxis for RINV in patients receiving radiotherapy to abdomen/pelvis, including total body irradiation (TBI). Primary endpoints were complete control of nausea and complete control of vomiting during acute and delayed phases. Secondary endpoints included use of rescue medication, quality of life (QoL) and incidence of adverse events. RESULTS: Seventeen RCTs were identified. Among patients receiving radiotherapy to abdomen/pelvis, our meta-analysis showed that prophylaxis with a 5-hydroxytryptamine-3 receptor antagonist (5HT3 RA) was significantly more efficacious than placebo and dopamine receptor antagonists in both complete control of vomiting [OR 0.49; 95% confidence interval (CI): 0.33-0.72 and OR 0.17; 95% CI: 0.05-0.58 respectively] and complete control of nausea (OR 0.43; 95% CI: 0.26-0.70 and OR 0.46; 95% CI: 0.24-0.88 respectively). 5HT3 RAs were also more efficacious than rescue therapy and dopamine receptor antagonists plus dexamethasone. The addition of dexamethasone to 5HT3 RA compared to 5HT3 RA alone provides a modest improvement in prophylaxis of RINV. Among patients receiving TBI, 5HT3 RA was more effective than other agents (placebo, combination of metoclopramide, dexamethasone and lorazepam). CONCLUSIONS: 5HT3 RAs are more effective than other antiemetics for prophylaxis of RINV in patients receiving radiotherapy to abdomen/pelvis and TBI. Future RCTs should investigate the efficacy of newer agents such as substance P neurokinin 1 receptor antagonists in addition to 5HT3 RAs in prophylaxis of RINV during both acute and delayed phases.

The nuclear hormone-receptor family in the brain: classics and orphans.

Nuclear hormone receptors comprise a superfamily of over 40 transcription factors. About half of them are classical receptors for lipophilic ligands such as steroids and vitamins. Almost all of these true receptors are present in the brain, where they transduce chemical signals from endocrine organs or signals of nutritional origin into cellular responses. The other members resemble the classical receptors in structure, but have no known ligands, and are hence called 'orphan receptors'. The issue of whether ligands for nuclear orphan receptors exist is controversial. Evidence is emerging that orphan receptors might be activated by signal transduction pathways or might be constitutive enhancers or repressors that interact with the classical receptors. Thus, nuclear orphan receptors are placed in strategic positions in the regulation of gene expression in the nervous system.

Mutations in RNA: a first example of molecular misreading in Alzheimer's disease.

In the past decade, considerable progress has been made in the understanding of the neurodegenerative changes that occur in Alzheimer's disease (AD). Knowledge about this disease is based mainly on studies of inherited forms of AD, although most cases of AD are of the non-familial type. Recently, a novel type of mutation in 'vulnerable' dinucleotide repeats in messenger RNA was discovered in AD patients: in this type of mutation a mutated transcript is produced from a correct DNA sequence, a process that we call 'molecular misreading'. The resulting mutated '+1 proteins' are prominent neuropathological hallmarks of AD and they are present in most elderly non-demented people also. This suggests that the dinucleotide deletions in transcripts could be one of the earliest events in the neuropathogenesis of AD and an important factor in normal aging.

Neurohypophysial dysmorphogenesis in mice lacking the homeobox gene Uncx4.1.

A number of transcription factors have been implicated in the development of the hypothalamo-neurohypophysial system (HNS). Null mutations for these factors caused severe defects in proliferation, migration and survival during early embryogenesis. While they have informed about early events of HNS developments no insights in mechanisms of late development and maturation of this major peptidergic system have been obtained as yet. In a screen for adult-expressed homeobox genes we identified Uncx4.1 as a gene expressed in adult and embryonic magnocellular neurons of the (HNS). Null mutation of Uncx4.1 left these neurons viable and able to express neuropeptides. However, the connectivity of magnocellular neurons with posterior pituitary elements was compromised. As a consequence neuronal fibres traversed to the adenohypophysis. The penetrance of this phenotype was about 50%. The data show a selective role of Uncx4.1 in controlling the development of connections of hypothalamic neurons to pituitary elements, allowing central neurons to reach the peripheral blood circulation and to deliver hormones for control of peripheral functions.

Minor disturbances in central nervous system function in familial neurohypophysial diabetes insipidus.

Familial neurohypophysial diabetes insipidus (FNDI) is caused by a defect in vasopressin synthesis and release as a result of a heterozygous mutation in the gene for the vasopressin prohormone. The predominant characteristic of FNDI is excessive thirst and urine production. However, vasopressin not only has peripheral endocrine effects, but also regulates numerous brain functions. We investigated whether central functions are affected in FNDI, by studying neuropsychological functioning of 23 affected members (15 males, 8 females) of a large family carrying a T/G transition mutation at nucleotide 2110 (codon 116) of the vasopressin prohormone gene (Cys116Gly). The relatively large number of family members with FNDI made it possible to compare cognitive and other CNS effects in these subjects with those of family members without FNDI. Thirty-seven adult volunteers (20 males, 17 females) from the same family and 11 non-family members (2 males, 9 females) from northern part of The Netherlands were tested. The mean age of the subjects was 35+/-12 years. Of the 63 quantified neuropsychological parameters few were statistically different between the subjects with FDNI and control subjects. Memory retrieval processes and sustained attention were worse in the subjects with FDNI. Moreover, these individuals reported significantly fewer symptoms of agoraphobia and miscellaneous symptoms, and had significantly lower scores on a scale measuring anger. The performance of FNDI subjects on an auditory verbal learning test (the 15-word test learning trial) was worse, but not significantly so, than that of the subjects without FDNI. There were subjective complaints of forgetfulness and slow recalls and those were observed in daily life by non-affected family members. These moderate differences in neuropsychological performance indicate that in human FNDI parvocellular vasopressin systems that supply the brain may be less affected or give no such serious disabilities, than the magnocellular hypothalamo-neurohypophysial system that provides vasopressin for endocrine regulation of water homeostasis.

Vacuum-assisted closure therapy for infected perineal wounds after abdominoperineal resection. A retrospective cohort study.

INTRODUCTION: Perineal wound complications are a main problem after abdominoperineal resection (APR). There is little evidence concerning perineal wound management. This study describes and evaluates the role of vacuum-assisted closure (VAC) therapy in wound management strategies of perineal wound infections after APR. METHODS: Patients undergoing APR for malignant disease between January 2007 and January 2013 were identified retrospectively. Data regarding occurrence and management of perineal wound complications were collected. Perineal wound infections were classified into minor or major complications and time to wound healing was measured. Time to wound healing was compared between patients receiving routine care or with additional VAC therapy. RESULTS: Of 171 included patients, 76 (44.4%) had minor and 36 (21.1%) major perineal wound infections. Management of major infected perineal wounds consisted of drainage (n = 16), debridement (n = 4), drainage combined with debridement (n = 4), VAC therapy alone (n = 5), or VAC therapy combined with other treatments (n = 7). Median duration of perineal wound healing in major infected wounds was 141 days (range 17-739). Median time to wound healing was not different in patients treated with (172 days, range 23-368) or without VAC therapy (131 days, range 17-739). DISCUSSION AND CONCLUSION: In this study, VAC therapy did not shorten time to wound healing. However, prospective studies are required to investigate the role of VAC therapy in management of infected perineal wounds after APR. Up to then, wound management will remain to be based on clinical perception and 'gut-feeling'.

Association of Cell Adhesion Molecules Contactin-6 and Latrophilin-1 Regulates Neuronal Apoptosis.

In view of important neurobiological functions of the cell adhesion molecule contactin-6 (Cntn6) that have emerged from studies on null-mutant mice and autism spectrum disorders patients, we set out to examine pathways underlying functions of Cntn6 using a proteomics approach. We identified the cell adhesion GPCR latrophilin-1 (Lphn1, a.k.a. CIRL1/CL, ADGRL1) as a binding partner for Cntn6 forming together a heteromeric cis-complex. Lphn1 expression in cultured neurons caused reduction in neurite outgrowth and increase in apoptosis, which was rescued by coexpression of Cntn6. In cultured neurons derived from Cntn6-/- mice, Lphn1 knockdown reduced apoptosis, suggesting that the observed apoptosis was Lphn1-dependent. In line with these data, the number of apoptotic cells was increased in the cortex of Cntn6-/- mice compared to wild-type littermate controls. These results show that Cntn6 can modulate the activity of Lphn1 by direct binding and suggests that Cntn6 may prevent apoptosis thereby impinging on neurodevelopment.

Signalling through phospholipase C beta 4 is not essential for midbrain dopaminergic neuron survival.

The most prominent progressive neurodegenerative movement disorder, Parkinson's disease, is attributed to selective loss of dopamine neurons in the substantia nigra pars compacta, resulting in severe deficiency of dopamine. The homeo-domain gene, Pit x 3, is essential for proper development of midbrain dopaminergic neurons in the substantia nigra pars compacta and might be involved in midbrain dopaminergic survival pathways. The mGluR1-signaling downstream-effector phospholipase C beta 4 was identified in a suppression subtractive hybridization screen comparing wild-type and Pit x 3-deficient Aphakia midbrain dopaminergic neurons. Expression pattern analysis revealed that phospholipase C beta 4 was expressed in midbrain dopaminergic neurons of the substantia nigra pars compacta and part of the ventral tegmental area, whereas expression of mGluR1alpha was predominantly observed in the more vulnerable midbrain dopaminergic neurons in the lateral substantia nigra pars compacta. However, clear expression of phospholipase C beta 4 in spared midbrain dopaminergic neurons of Aphakia mice located in the ventral tegmental area, indicated that induction and maintenance of phospholipase C beta 4 expression is Pit x 3-independent in these neurons. Furthermore, we report here a normal distribution of midbrain dopaminergic cell bodies and axonal projection to the striatum in phospholipase C beta 4-/- mice, indicating that signaling of phospholipase C beta 4 is not essential for the survival of midbrain dopaminergic neurons.

Increased gabaergic input to ventral tegmental area dopaminergic neurons associated with decreased cocaine reinforcement in mu-opioid receptor knockout mice.

There is general agreement that dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens and prefrontal cortex play a key role in drug reinforcement. The activity of these neurons is strongly modulated by the inhibitory and excitatory input they receive. Activation of mu-opioid receptors, located on GABAergic neurons in the VTA, causes hyperpolarization of these GABAergic neurons, thereby causing a disinhibition of VTA dopaminergic neurons. This effect of mu-opioid receptors upon GABA neurotransmission is a likely mechanism for mu-opioid receptor modulation of drug reinforcement. We studied mu-opioid receptor signaling in relation to cocaine reinforcement in wild-type and mu-opioid receptor knockout mice using a cocaine self-administration paradigm and in vitro electrophysiology. Cocaine self-administration was reduced in mu-opioid receptor knockout mice, suggesting a critical role of mu-opioid receptors in cocaine reinforcement. The frequency of spontaneous inhibitory post-synaptic currents onto dopaminergic neurons in the ventral tegmental area was increased in mu-opioid receptor knockout mice compared with wild-type controls, while the frequency of spontaneous excitatory post-synaptic currents was unaltered. The reduced cocaine self-administration and increased GABAergic input to VTA dopaminergic neurons in mu-opioid receptor knockout mice supports the notion that suppression of GABAergic input onto dopaminergic neurons in the VTA contributes to mu-opioid receptor modulation of cocaine reinforcement.

Regulation of vasopressin messenger RNA levels in the small cell lung carcinoma cell line GLC-8: interactions between glucocorticoids and second messengers.

The role of glucocorticoids and second messenger systems in the regulation of the vasopressin (VP) gene was studied in the human small cell lung carcinoma cell line GLC-8. Small cell lung carcinoma GLC-8 cells express VP mRNA and contain both glucocorticoid and mineralocorticoid receptors. Treatment with the synthetic glucocorticoid dexamethasone when added alone at 10(-8) M had no effect on the VP mRNA level and decreased the level by 30% at 10(-6) M. However, the effect of dexamethasone changed to positive when cells were simultaneously treated with cAMP-enhancing agents. VP mRNA levels, which were elevated by 1.5- to 2-fold by the cAMP-enhancing agents alone, increased a further 1.5- to 3-fold by dexamethasone. Thus, the combined effect of dexamethasone and cAMP stimulation was a 3- to 7.5-fold increase in VP mRNA levels. Long term treatment with the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA) reduced the VP mRNA level by 75%. The TPA-suppressed VP mRNA levels could be up-regulated about 6-fold by simultaneous treatment with 8-bromo-cAMP. Dexamethasone did not alter the TPA-suppressed VP mRNA levels. These results indicate that both cAMP and protein kinase-C pathways as well as glucocorticoid receptors are involved in the regulation of VP mRNA levels and that these factors interact. This leads to a negative or positive response of VP gene expression to glucocorticoids in a state-dependent manner. The interactions may be of significance in a physiological context and relate to the different regulation of VP-expressing systems in the brain.