[The characteristics of the startle reflex to an acoustic stimulus in rats with hereditary stress-sensitive arterial hypertension: the effect of chronic stress in the prepuberty period]

Acoustic startle reflex was studied in young and adult rats with hereditary stress-induced arterial hypertension (HSIAH) in comparison with original normotensive Wistar strain. Immediate and long-lasting effects of chronic handling or chronic unpredictable stress at the age of 4 and 5 weeks on manifestations of the startle reflex were studied. The amplitude of the sensorimotor reaction was lower in both young (38-day-old) and adult (4-month-old) HSIAH rats than in age-matched normotensive Wistar rats. Young and adult hypertensives demonstrated significant inhibition of startle reflex when the startling stimulus was preceded by a weak prepulse. Such prepulse inhibition was not expressed in young or adult Wistar rats. Chronic handling as well as chronic unpredictable stress during the 4th and 5th weeks of life potentiated the startle amplitude in young HSIAH rats. The prepulse inhibition level did not depend on the chronic stress. The long-lasting effect of the prepubertal chronic stress depended on the type of the stress factors.

Lipid reactivity among men with a parental history of myocardial infarction

In the current study, we examined lipid and cardiovascular responses to an acute stressor among men with and without a parental history of myocardial infarction. 37 men were selected from a large group who completed medical history questionnaires and interviews. Twenty-two men who denied parental history of heart disease (negative parental history) were compared with 15 men with one or both parents who had suffered a myocardial infarction (positive parental history). Total cholesterol, high- and low-density lipoprotein cholesterol, triglycerides, heart rate, and blood pressure were measured at rest and during a videotaped speech stressor. Positive parental history men had significantly higher low-density lipoprotein cholesterol levels and blood pressure at baseline, significantly lower high-density lipoprotein cholesterol levels at baseline, and significantly larger total cholesterol and low-density lipoprotein cholesterol reactivity, relative to negative parental history men. Because parental history is a risk factor for subsequent cardiovascular morbidity and mortality, these data suggest that lipid reactivity to stress may be biologically important.

Neurological signs and psychomotor performance in patients with schizophrenia, their relatives and healthy controls

Schizophrenic patients (DSM-III-R) were consecutively recruited and 39 were included. Twenty-one were first-episode and 18 were chronic schizophrenic patients. Thirty of the patients were on neuroleptic medication. Thirty-three parents were included, of whom nine were classified as 'family history positive' and 22 as 'family history negative' of a disposition to psychosis. Fifty-five healthy controls volunteered. The subjects were investigated according to a protocol divided into neurological signs and psychomotor performance (finger-tapping rate, Purdue pegboard test, pronation-supination test, gait and hand-grasp strength). Seventy-eight percent of the patients and 7% of the controls were classified as globally aberrant in signs. The patients and their parents, classified as 'family history positive', exhibited a similar laterality pattern in a finger-tapping test improving performance with the preferred hand, significantly different from the performance of the 'family history negative' parents and normal subjects. Duration of illness, neuroleptic medication and negative symptoms were not related to the occurrence of neurological signs and psychomotor performance. These findings indicate that neurological aberrations are present at the onset of illness and that hereditary factors are associated with motor laterality.

[Thermal interhemispheric asymmetry of the brain in rats in a cataleptic state]

The rat brain thermal fields were studied using the thermoencephaloscopic technique in three experimental conditions: the genetic catalepsy (GC rat strain), cataleptic phase of an audiogenic epileptic seizure (Krushinskiĭ-Molodkina strain), and pharmacological catalepsy produced by haloperidol injection (Wistar rats). Irrespective of the experimental conditions, the state of catalepsy, accompanied by a decrease in the muscle tone and inhibition of motor reactions, was characterized by total asymmetric cooling of the brain cortex with the dominance of the right hemisphere. Temperature difference between the parieto-occipital areas of the right and left hemispheres reached 0.3-0.6 degree C.

Path analysis of P300 amplitude of individuals from families at high and low risk for developing alcoholism

BACKGROUND

A substantial amount of evidence exists suggesting that P300 amplitude in childhood is a risk marker for later development of alcohol dependence. There is evidence that P300 amplitude is heritable. The goal of the present study was to determine if patterns of transmission differed in families who were either at high or low risk for developing alcohol dependence.

METHODS

Auditory P300 was recorded from 536 individuals spanning three generations. The path analytic TAU model was used to investigate the familial transmission of P300 amplitude in the two independent samples of families.

RESULTS

Transmission of P300 in high-risk families most likely followed a polygenic model of inheritance with significant parent-to-offspring transmission. Parent-to-offspring transmission was significantly greater in high-risk than low-risk families. Total phenotypic variance due to transmissible factors was greater in low-risk families than in high-risk families, however. A somewhat unexpected finding was the substantial correlation between mates for P300 amplitude in both high- and low-risk families.

CONCLUSIONS

P300 is transmissible in families. Differences exist in the pattern of transmission for P300 in families at high and low risk for alcoholism.

Platelet aggregation in young men with contrasting predisposition to high blood pressure

In essential hypertension, abnormal platelet function may induce vasospasm and predispose to thrombotic vascular occlusion. We studied in vitro aggregability in platelets from young men with contrasting predisposition to hypertension, defined by their own blood pressure and blood pressures of their parents. Among offspring of parents with low blood pressure, higher blood pressure was associated with impaired aggregation in response to epinephrine (2 x 10(-8) to 5 x 10(-6) mol/L), which was unaffected by endothelin-1 (10(-9) mol/L). By contrast, among offspring of parents with high blood pressure, higher blood pressure was associated with normal aggregation to epinephrine and potentiation of the primary phase of aggregation by endothelin-1. We conclude that enhanced platelet sensitivity to endothelin-1 appears to be a feature of the familial predisposition to hypertension, rather than a nonspecific consequence of high blood pressure.

The Munich vulnerability study on affective disorders: overview of the cross-sectional observations at index investigation

BACKGROUND

An altered nocturnal sleep pattern and a dysfunction of the hypothalamic-pituitary-adrenocortical system are neurobiological abnormalities typical for depression. A persistence of these neurobiological alterations during remission has been shown to be associated with an increased risk for a relapse. However, it remains unclear whether these persisting abnormalities are trait markers indicative of an increased vulnerability for affective disorders or only represent 'biological scars' acquired during past episodes. Thus, respective examinations need to be performed in the premorbid state in order to answer this open question.

METHODS

In the present article we have summarized the various results of the index investigation of a prospectively designed study in which we investigated 54 healthy first-degree relatives (high-risk probands; HRPs) of patients with an affective disorder using polysomnography, the combined dexamethasone corticotropine-releasing hormone (DEX-CRH) test and psychometric measurements.

RESULTS

In the cross-sectional part of this study the HRPs, as a group, exhibited a 'depression-like' sleep EEG profile and DEX-CRH test result, while their psychometric profile was characterized by elevated scores on the measures 'Rigidity' and 'Autonomic lability'. On an individual level, 35% of the HRPs were identified as conspicuous in at least two of the three areas under investigation.

CONCLUSIONS

The question of whether these abnormalities do indeed reflect trait markers indicative of an increased vulnerability for depression will be answered by the longitudinal part of the study that allows for the retrospective identification of the premorbid status of those HRPs who develop an affective disorder during the follow-up period.

Amplitude of visual P3 event-related potential as a phenotypic marker for a predisposition to alcoholism: preliminary results from the COGA Project. Collaborative Study on the Genetics of Alcoholism

Recent data collected at six identical electrophysiological laboratories from the large national multisite Collaborative Study on the Genetics of Alcoholism provide evidence for considering the P3 amplitude of the event-related potential as a phenotypic marker for the risk of alcoholism. The distribution of P3 amplitude to target stimuli at the Pz electrode in individuals 16 years of age and over from 163 randomly ascertained control families (n = 687) was compared with those from 219 densely affected alcoholic families (n = 1276) in which three directly interviewed first-degree relatives met both DSM-III-R and Feighner criteria at the definite level for alcohol dependence (stage II). The control sample did not exclude individuals with psychiatric illness or alcoholism to obtain incidence rates of psychiatric disorders similar to those of the general population. P3 amplitude data from control families was converted to Z-scores, and a P3 amplitude beyond 2 SD's below the mean was considered an "abnormal trait." When age- and sex-matched distributions of P3 amplitude were compared, members of densely affected stage II families were more likely to manifest low P3 amplitudes (2 SD below the mean) than members of control families, comparing affected and unaffected offspring, and all individuals; all comparisons of these distributions between groups were significant (p < 0.00001). P3 amplitude means were also significantly lower in stage II family members, compared with control family members for all comparisons, namely probands, affected and unaffected individuals (p < 0.0001), and offspring (p < 0.01). Furthermore, affected individuals from stage II families, but not control families, had significantly lower P3 amplitudes than unaffected individuals (p < 0.001). Affected males from stage II families had significantly lower P3 amplitudes than affected females (p < 0.001). Recent linkage analyses indicate that visual P3 amplitude provides a biological phenotypic marker that has genetic underpinnings.