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Biomedical subjects

A Concu

Publications and source records attributed to A Concu.

31 records · Page 2Linked to original sources
PubMed1979

Respiratory ventilation during muscular contraction in man.

Brief contraction of arm muscles affects respiratory ventilation either by increasing respiratory frequency or by increasing the instantaneous flow. Both these changes occur at a time subsequent to muscle contraction and can be attributed to a reflex mechanism originating from the muscles.

Adult↗
PubMed1978

Intranigral kainic acid: evidence for nigral non-dopaminergic neurons controlling posture and behavior in a manner opposite to the dopaminergic ones.

The unilateral, intranigral administration of kainic acid (k.a.) produced a syndrome characterized by early sequelae of contra- and ipsilateral circling and by a chronic contralateral turning associated with moderate loss of neurons in the pars reticulata. The acute contralateral circling seems to be related to dopaminergic nigro-neostriatal neuron stimulation, since it was prevented by previous intranigral injections of 6-OHDA. The acute ipsilateral circling and the chronic contralateral turning, on the other hand, seem to be independent of the integrity of the dopaminergic system and may be due to an initial stimulation, followed by destruction, of a nigral neuronal system which mediates turning behavior in a manner opposite to that of nigro-striatal dopamine. Treatment with D-amphetamine or apomorphine changed the contralateral into ipsilateral turning, while haloperidol potentiated the contralateral turning. Bilateral injection of k.a. into the nigra resulted in chronic stereotyped sniffing and gnawing, which were not inhibited by haloperidol. Moreover, haloperidol did not produce catalepsy in these animals. It is suggested that the intranigral k.a. injection destroyed a neuronal system antagonistic to dopamine and resulted in a reduction of the response to DA-receptor stimulation of the c. striatum.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1973

[Study on the absorption and utilization of D-galactose and D-glucose by liver and muscular tissue in the albino rat].

In order to compare the disposition of D-galactose and D-glucose in various organs of the rat, we have measured the amount of 14C-galactose and 14C-glucose present in the enteric canal, blood, muscle and liver, 2h. after the oral administration of the labelled esoses. Our results show that the two esoses are ebsorbed almost completely and to the same extent by two hours after their administration, Galactose has a longer half-life than glucose, being more slowly utilized in the synthesis of glycogen in liver and muscle.

Animals↗
PubMedDate not supplied

Differences in cardiovascular profiles induced by mental arithmetic and by hand-eye task.

Five young, healthy male students performed two different psychophysical tests each lasting 1 min. The first test (A) consisted of mental arithmetic with digiting of results on a keyboard; the second test (G) consisted of playing an electronic game based on hand-eye coordination. Before and during each test, subjects remained seated with their thoraxes connected to an impedance cardiography monitor which gave, non invasively, beat-by-beat values of heart rate (HR), cardiac output (CO), stroke volume (SV) and left ventricle ejection time (VET). Systolic (SBP) and diastolic (DBP) arterial blood pressures were measured by means of a sphygmomanometer and total peripheral vascular resistance (TPR) and mean systolic ejection rate (MSER) were calculated. During test A, CO (A = +30%, G = +14%), HR (A = +26%, G = +2%) and SBP (A = +16%, G = +10%) increased more than during test G, while SV (A = +3%, G = +12%) and MSER (A = +11%, G = +14%) increased less and TPR (A = -13%, G = -7%) and VET (A = -7%, G = -2%) decreased more than in G. It was concluded that the analysis of a more complete cardiovascular profile may enhance distinctions among the behavioural stressors that induced different combinations in cognitive and sensory-motor responses.

Adult↗