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Biomedical subjects

M Decandia

Publications and source records attributed to M Decandia.

At least 19 recordsLinked to original sources
PubMed1991

Group I fibers: pressor reflex and cardiac activity.

Experiments were performed on cats to see whether stimulation of group I afferent fibers from gastrocnemius-soleus muscles induced changes in cardiac activity, in addition to the increase in systemic arterial pressure already established. The results show that the increase in arterial pressure is accompanied by an increase in systolic left ventricular pressure, without any significant changes in cardiac inotropism and chronotropism. It is concluded that the cardiac innervation is not an important efferent pathway of the pressor reflex evoked by stimulating group I afferent fibers, and that the reflex increase in arterial pressure depends mainly on an increase in peripheral vascular resistance.

Afferent Pathways↗
PubMed1990

Group I afferent fibers: effects on cardiorespiratory system.

In anesthetized cats, we examined cardiorespiratory activity during excitation of large afferent fibers from muscle proprioceptors. We found that selective stimulation of group I fibers with electric impulses at 200-300 Hz induces an increase in pulmonary ventilation from control value (mean +/- SE) of 486 +/- 8 to a maximum of 544 +/- 8 ml/min and an increase in mean systemic arterial pressure from control value of 151 +/- 2 to a maximum of 160 +/- 2 mmHg. Neither of these increases was produced by the same stimulation when applied during anodal block of volleys of group I fibers. Hyperpnea could be obtained independently from changes in cardiovascular activity, and the pressor response could be obtained during artificial ventilation at constant tidal volume after curarization. Consequently, it appears that respiratory and cardiovascular responses to stimulation of group I fibers can be independent of each other.

Afferent Pathways↗
PubMed1989

[Effect of phentolamine on the reflex increase in arterial pressure].

Experiments were carried out in anaesthetized and curarized cats to study the effects of the alpha-blocker phentolamine on arterial pressor response to stimulation of group I afferent fibers from gastrocnemius-soleus muscles. It has been found that increasing doses of phentolamine given i.v. cause a decreasing pressor response until complete disappearance occurs at 2.5 mg/Kg. It is concluded that pressor response is present only when the adrenergic control system is effective and, therefore, it is due mainly to an increase in peripheral vascular resistances.

Animals↗
PubMed1979

[Respiration during isometric contraction of the flexor or extensor muscles of the arm in humans].

An increase in the instantaneous pulmonary flow and a decrease in the respiratory frequency has been found in man as a consequence of isometric contraction of either flexor or extensor muscles of the elbow. The delay of 200 to 900msec between the onset of the muscle contraction and the beginning of the flow increment suggests that the respiratory system increases its activity due to the proprioreceptor activation. As there is no significant difference in the results obtained during flexor or extensor contraction, the contribution of the two different receptor groups appears to be the same.

Adult↗
PubMed1979

[Effects of passive movement of the arm on respiration in humans].

Cyclic passive movements of the right arm at 1Hz induce an increase in pulmonary ventilation in man. This results from an increase in frequency of the respiratory cycles, mainly due to a shortening of the expiratory phase, and from an increase of the instantaneous flow. The delay between the beginning of the arm movements and the onset of the increase in flow is about 450msec.

Adult↗
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↗