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Biomedical subjects

T Hecht

Publications and source records attributed to T Hecht.

At least 55 records · Page 3Linked to original sources
PubMed1976

Hypertension in adult rats treated neonatally with angiotensin.

Rats treated neonatally with angiotensin showed labile hypertension in adulthood. This finding may suggest a permanently changed responsiveness of a central nervous controller of the cardiocirculatory system caused by angiotensin-induced hypertension during brain differentiation.

Angiotensin II↗
PubMed1976

[Glucose tolerance of postnatally stress-sensitized albino rats following chronic emotional stress in adulthood].

Male albino rats were used to study the effect of electrical stimulation in the postnatal phase (day 1--15) leading to short-time convulsions and cyanosis lasting about 10 min in 5-month-old animals upon the development of glycemic dysregulation induced by emotional stress. The studies involving i.p. glucose administration show that a 3-week stress influence on postnatally stimulated animals caused heavier changes of glycemic regulation than with non-pretreated animals. These results suggest a stress sensitization occurring in the postnatal phase and are discussed in connection with the "stress-sensitive risk personality" by R. BAUMANN. Further studies have shown that the postnatal stress sensitiveness is reversible and cannot only be compensated by a rest period of several weeks but may even cause stress resistance on renewed stressing for three weeks.

Animals↗
PubMed1976

[The role of uncertainty in the conditioned-reflex learning behavior for selected cardiovascular functions].

As a contribution to quantitative analysis of exogenous stress action, the role of probability learning (probability stress, probability affirmation) for selected cardio-vascular functions was studied in 25 albino rats and 8 dogs. It has been shown in the rats learning with probability stress that a dependence exists between stress probability, on the one hand, and conditional-reflectory processes and systolic blood pressure rise, on the other, that is, the pathogenic action of probability stress increases from a probability of p = 1.0 to p = 0.5. An analogous picture was found with the probability affirmation being applied in dogs. While a probability affirmation with p = 1.0 promoted adaptational processes, a value of p = 0.5 led to experimental neurosis, tachycardia and ECG alterations. The results obtained are discussed in context with the information entropy and information theory of emotions.

Animals↗
PubMed1976

[The significance of stress intensity for the emotional and visceral reactivity, especially for blood pressure regulation].

The influence of light, medium, and heavy chronic stress upon cerebro-visceral functions following 3 and 5 weeks of daily stress exposure was examined. The following results were obtained: Light stress produced no changes of cerebro-visceral functions. Medium stress restricted the learning and memory capacity, increased systolic blood pressure, fasting blood sugar and adrenal weights. The B-cells of the pancreatic islets showed degranulations of varying intensity. Heavy stress diminished the learning and memory capacity, increased adrenal weights and led to hypergranulation of the pancreatic B-cells. Blood sugar and blood pressure values fall within physiological limits. Load tests, however, revealed in these animals symptoms of premorbid states. Since throughout the period of observation, light stress stablized the regulation processes, medium stress induced early stages of pathological processes, and heavy stress caused premorbid states, no linearity could be established between the load intensity and the changes of cerebro-visceral functions.

Adrenal Glands↗
PubMed1976

[Correlations between hippocampus function and stressed learning and their effect on cerebro-visceral regulation processes].

43 male albino rats were investigated to find out what are the effects of bilateral exclusion of pes hippocampus structures upon the development of arterial hypertension released by learning stress exposure. The following results were obtained: 5 weeks of stress exposure (learning load and heavy learning load) caused disturbances of information-processing events of the central nervous system in all the animals with hippocampal lesions. Systolic blood pressure values, fasting blood sugar values, and adrenal weights fall within the physiological range. The B-cells of the pancreatic islets show hypergranulation. Functional tests of the blood pressure under exercise load, and of blood sugar under glucose load revealed normal reactions in animals with hippocampal lesions. In animals with intact brains the same stress exposure caused pathologic malfunctioning (under learning stress) or even premorbid states. The results being considered in relation to the pathogenesis of arterial hypertension show that the exclusion of circumscribed areas of the hippocampus prevents the development of permanent, stress-induced emotional excitations spreading into the viscerum.

Animals↗
PubMed1975

[Biphasic effect of angiotensin II on conditioned reflectory reaction patterns in albino rats].

40 male albino rats were used to investigate the influence of one single i. v. dose of 10 ng/kg Angiotensin II upon established and stabilized conditional-reflectory response pattern (two-dimensional conditional-reflectory decision process and periodicities of conditional-reflectory processes). At normotonous blood-pressure values, Angiotensin II exerted a biphasic action on the conditional-reflectory response pattern. In the first phase of action (up to 30 min after injection) there prevailed centralnervous inhibition processes, while the second phase of action (30-70 min after injection) was marked by a general centralnervous excitation, which is reflected by extremely short times of response, and a pronounced sensitivity to optic, acoustic and tactile stimuli. The decision capacity of the animals was considerably reduced in both phases. The periodicities of conditional-reflectory processes (duration of periods in the minute range) are strongly disturbed in the first phase of action, and tend to normal in the second phase. Furthermore, Angiotensin II was found to have a selective, hierarchically ordered influence with regard to the duration and intensity of action. Thus, the information processing activity of the CNS underwent most pronounced changes. The centralnervous regulatory functions were less affected; the blood pressure regulation showed little and transient influence by Angiotensin II. In the discussion, the neurotropic and algogenic action of Angiotensin II, and the relation of the octapeptide effect with pathogenetic mechanisms of experimental neurotically induced hypertonia are dealt with.

Angiotensin II↗
PubMed1975

[Effect of angiotensin II on the conditional relfex response patterns of neurotic albino rats].

The effect of one single dose of 10 ng Angiotensin II/kg body weight upon affirmed conditional-reflectory response patterns (two-dimensional conditional-reflectory decision process and periodicities of conditional-reflectory processes) was studied in 50 male albino rats in which a neutrotically induced hypertensive blood pressure regulation had been elicited by stress exposure for 135 days. Contrary to healthy animals in which Angiotensin II was demonstrated to act in a biphasic manner, the neurotic animals revealed a monophasic action manifesting itself by a generalized centralnervous excitation. It was noticed, furthermore, that the information processing and regulatory processes of the CNS are considerably disturbed. The chronically hypertensive systolic blood pressure values of neurotic animals, like in healthy ones, show a brief, transient rise immediately following administration of Angiotensin II. These results are not only another proof of a neurotropic component of Angiotensin II action, but they show also that this action allows one to judge the state of disturbed nervous functions. The correlation of the neurotropic effect of Angiotensin II with pathogenetic mechanisms of experimental neurotically induced hypertension is discussed.

Angiotensin II↗
PubMed1975

[Significance of different social factors active in the course of ontogenesis, for the effectiveness of chronic stress influences upon cerebro-visceral regulation processes of albino rats].

Fifty male albino rats were used to study how social factors (animals kept in large groups with playing-cage character, or in social isolation by solitary maintenance) are reflected in the responsiveness of cerebro-visceral regulation processes to chronic stress exposure. The following results were obtained: Animals kept from the 12.-30. week of life in social companionship and, additionally, exposed to chronic stress influences, proved to be greatly resistant to permanent load. This effect is referred to the rich supply of social afferentations and to the pronounced stimulation of proprioreceptive reafference as a result of social communication and motor activity. Animals kept, after preceding large-group maintenance, in social isolation from the 17.-30. week and simultaneously being exposed to the same stress influence as the animals in the playing cage, showed symptoms of an early stage of neurotically induced, arterial hypertension. Here, the chronic lack of socially determined, adequate environmental afferentation and of proprioreceptive reafference, as was typical of solitary maintenance, proved to be a factor enhancing the pathological predisposition of the organism under extreme environmental conditions.

Adaptation, Physiological↗