Are spatial memories strengthened in the human hippocampus during slow wave sleep?

In rats, the firing sequences observed in hippocampal ensembles during spatial learning are replayed during subsequent sleep, suggesting a role for posttraining sleep periods in the offline processing of spatial memories. Here, using regional cerebral blood flow measurements, we show that, in humans, hippocampal areas that are activated during route learning in a virtual town are likewise activated during subsequent slow wave sleep. Most importantly, we found that the amount of hippocampal activity expressed during slow wave sleep positively correlates with the improvement of performance in route retrieval on the next day. These findings suggest that learning-dependent modulation in hippocampal activity during human sleep reflects the offline processing of recent episodic and spatial memory traces, which eventually leads to the plastic changes underlying the subsequent improvement in performance.

Vasopressin-neurophysin and DST in major depression: relationship with suicidal behavior.

The purpose of the present study was to assess if AVP-neurophysin is associated with hypercortisolemia and suicidal behaviour in depressed patients. The study included 28 patients subgrouped into suicide attempters (n=13) and nonattempters (n=15). We assessed basal AVP-neurophysins concentrations and post-dexamethasone (DST) cortisol levels. Concentrations of AVP-neurophysins did not differ between DST suppressors and nonsuppressors: 0.29+/-0.13 ng/ml vs 0.36+/-0.21 ng/ml, (F=1.1, df=1, 27, p=0.30). Suicide attempters did not differ from nonattempters for AVP-neurophysins levels. Our results fail to support a role of AVP in the early cortisol escape.

The short allele of the serotonin transporter promoter polymorphism influences relapse in alcohol dependence.

AIMS: The short (S) allele of the serotonin transporter gene promoter polymorphism (5-HTTLPR) contributes to the risk of alcohol dependence and co-occurring clinical features. We studied the putative link between this allele and relapse. METHODS: 48 alcohol-dependent male patients were recruited and genotyped for the 5-HTTLPR. Relapse to alcohol drinking was monitored during 3 months after standardized withdrawal. RESULTS: The S allele was significantly associated with relapse (p = 0.008) while no other factor that was measured played a significant role. CONCLUSIONS: The S allele of the 5-HTTLPR polymorphism may influence the risk of relapse in abstinent alcohol-dependent patients, possibly through intermediate phenotypes.

5-Hydroxytryptamine 1A receptors, major depression, and suicidal behavior.

BACKGROUND: Several lines of evidence suggest a clear relationship between serotonin (5-hydroxytryptamine, 5-HT) hypoactivity and suicidal behavior across several psychiatric diagnoses. Few data are available, however, regarding the possible specific role of 5-HT1A receptors in the biology of suicidality. Therefore, the aim of our study was to use a neuroendocrine strategy to test the hypothesis of a role for 5-HT1A receptors in the biology of suicidal behavior. METHODS: Hormonal (adrenocorticotropic hormone [ACTH], cortisol, prolactin [PRL]) and temperature responses after administration of flesinoxan, a highly potent and selective 5-HT1A receptor full agonist, were assessed in 40 inpatients with major depression, divided into two subgroups (20 suicide attempters and 20 nonattempters), compared with 20 normal control subjects matched for gender and age. RESULTS: Compared with nonattempters, suicide attempters exhibited significantly lower PRL (p = .01), cortisol (p = .014), and temperature (p = .0002) responses. Prolactin (p = .007), cortisol (p = .04), and temperature (p = .00003) responses were also decreased in suicide attempters compared with normal control subjects. In contrast, we did not observe any significant differences in hormonal or temperature responses to flesinoxan between depressed patients without a history of suicide attempt and normal control subjects. CONCLUSIONS: The present study tends to confirm the role of 5-HT and more specifically 5-HT1A receptors in the biology of suicidal behavior in major depression.

Hormonal and temperature responses to the 5-HT1A receptor agonist flesinoxan in normal volunteers.

RATIONALE: Flesinoxan is a highly potent and selective 5-HT(1A) agonist and appears to be a potentially interesting neuroendocrine serotonergic probe. OBJECTIVES: We assessed hormonal (ACTH, cortisol, prolactin and growth hormone) and temperature responses to flesinoxan in normal volunteers. METHODS: In a double-blind placebo-controlled study, single doses of 0.5 mg and 1 mg were injected over 10 min into 12 healthy male volunteers at 1-week intervals. Temperature and hormonal responses were measured at times -30, 0, 15, 30, 60, 90, and 120 min. RESULTS: Flesinoxan induced a significant and dose-dependent increase in adrenocorticotropic hormone (ACTH), cortisol, prolactin (PRL), growth hormone (GH) and a decrease in body temperature. Tolerance to flesinoxan was excellent. CONCLUSIONS: These results showed the role of 5-HT(1A) mechanisms in the PRL, ACTH, cortisol, GH, and temperature responses to flesinoxan. In the present study, flesinoxan appears a very promising serotonergic neuroendocrine probe.

The TaqI A DRD2 polymorphism in type II alcohol dependence: a marker of age at onset or of a familial disease?

Cloninger's type II is a severe, early-onset, male-limited, and genetically influenced, impulsive form of alcoholism. Significant association has been reported between the A1 allele of the D2 dopamine receptor (DRD2) gene, substance misuse and personality traits of impulsivity and novelty seeking. We assessed the association between the TaqI A DRD2 gene polymorphism with Cloninger's typology and family history of alcohol abuse, which is thought to be more frequent in type II alcoholics. Fifty-one male alcohol-dependent patients were discriminated between type I and type II according to age at onset of alcohol-related problems and interviewed about family history of alcoholism. The associations between DRD2 (A1 or A2 alleles), family history, and typology were assessed by Pearson's chi-square test. Although typology was not associated with the studied polymorphism, a higher rate of general family history of alcohol abuse was still observed in type II patients (chi(2)(1)=4.53; P=.033). Furthermore, the A1 allele of the DRD2 was significantly associated with paternal history of alcoholism (chi(2)(1)=4.66; P=.031) and male, first-degree, collateral history of alcoholism (chi(2)(1)=4.40; P=.036). Age at onset of alcohol-related problems as main discriminator between type I and type II alcohol dependence does not seem to be associated by the TaqI A DRD2 polymorphism. However, the A1 allele of the DRD2 may be a marker of male familial alcoholism, which has been associated with type II alcohol dependence.

Catecholamine and HPA axis dysfunction in depression: relationship with suicidal behavior.

A large body of evidence suggests a potential role for catecholaminergic function as a possible biological factor in the control of suicidal behavior. Recently, we have used a neuroendocrine strategy to study dopaminergic and noradrenergic activities in depressed suicide attempters. However, some problems are associated with the use of growth hormone (GH) response to catecholaminergic challenge, because GH release could be decreased by a direct effect of corticosteroids at the pituitary level. Therefore, the purpose of the present study was to assess GH response to both apomorphine, a dopaminergic agonist, and clonidine, an alpha2-adrenergic agonist, according to the dexamethasone suppression test (DST) status in a sample of 20 major depressed inpatients with a history of suicide attempt compared with nonattempters. Our results tended to show that hypercortisolemia as assessed by post-DST cortisol values did not inhibit GH response to apomorphine or clonidine, suggesting that hypothalamo-pituitary-adrenal axis overactivity does not explain the impaired GH response to apomorphine in major depressed patients with a history of suicide attempt.

Heroin-assisted treatment as a response to the public health problem of opiate dependence.

Injection drug use (involving the injection of illicit opiates) poses serious public health problems in many countries. Research has indicated that injection drug users are at higher risk for morbidity in the form of HIV/AIDS and Hepatitis B and C, and drug-related mortality, as well as increased criminal activity. Methadone maintenance treatment is the most prominent form of pharmacotherapy treatment for illicit opiate dependence in several countries, and its application varies internationally with respect to treatment regulations and delivery modes. In order to effectively treat those patients who have previously been resistant to methadone maintenance treatment, several countries have been studying and/or considering heroin-assisted treatment as a complementary form of opiate pharmacotherapy treatment. This paper provides an overview of the prevalence of injection drug use and the opiate dependence problem internationally, the current opiate dependence treatment landscape in several countries, and the status of ongoing or planned heroin-assisted treatment trials in Australia, Canada and certain European countries.