Reflex effects on the heart of stimulating left atrial receptors

Furnival, Colin; Snow, H. M.

doi:10.1113/jphysiol.1971.sp009627

Cited by 59 publications

(33 citation statements)

References 28 publications

(44 reference statements)

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“…The opposing result may be due to the presence of confounding physiological mechanisms (e.g., arterial baroreflex) in their study and possibly species differences. Our finding also contrasts with the experimental study of Furnival et al (9), in which the maximal LVP derivative did not change with left atrial balloon distension in anesthetized dogs. Other than the use of different ventricular contractility indices, it is difficult to come up with a reason explaining their result with our finding and the results of Karim et al (10) and especially Kurz et al (12).…”

contrasting

confidence: 57%

“…By contrast, Karim et al (10) demonstrated that cardiac sympathetic nerve activity increases, while renal sympathetic nerve activity decreases, in response to stimulation of the cardiopulmonary baroreflex via left atrial balloon distension in anesthetized dogs. Furnival et al (9) reported that the maximal derivative of left ventricular pressure (LVP) does not significantly change following left atrial balloon distension in anesthetized dogs. By contrast, Kurz et al (12) showed that the maximal LVP derivative (adjusted by LVP to compensate for preload) increased using a similar preparation with some or none of the potential confounding mechanisms (e.g., carotid sinus baroreflex) blocked.…”

mentioning

confidence: 99%

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Stimulation of the cardiopulmonary baroreflex enhances ventricular contractility in awake dogs: a mathematical analysis study

Sala‐Mercado

Moslehpour

Hammond

et al. 2014

American Journal of Physiology-Regulatory, Integrative and Comp

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-The cardiopulmonary baroreflex responds to an increase in central venous pressure (CVP) by decreasing total peripheral resistance and increasing heart rate (HR) in dogs. However, the direction of ventricular contractility change is not well understood. The aim was to elucidate the cardiopulmonary baroreflex control of ventricular contractility during normal physiological conditions via a mathematical analysis. Spontaneous beat-to-beat fluctuations in maximal ventricular elastance (E max), which is perhaps the best available index of ventricular contractility, CVP, arterial blood pressure (ABP), and HR were measured from awake dogs at rest before and after ␤-adrenergic receptor blockade. An autoregressive exogenous input model was employed to jointly identify the three causal transfer functions relating beat-to-beat fluctuations in CVP to E max (CVP ¡ Emax), which characterizes the cardiopulmonary baroreflex control of ventricular contractility, ABP to E max, which characterizes the arterial baroreflex control of ventricular contractility, and HR to E max, which characterizes the force-frequency relation. The CVP ¡ E max transfer function showed a static gain of 0.037 Ϯ 0.010 ml Ϫ1 (different from zero; P Ͻ 0.05) and an overall time constant of 3.2 Ϯ 1.2 s. Hence, E max would increase and reach steady state in ϳ16 s in response to a step increase in CVP, without any change to ABP or HR, due to the cardiopulmonary baroreflex. Following ␤-adrenergic receptor blockade, the CVP ¡ E max transfer function showed a static gain of 0.0007 Ϯ 0.0113 ml Ϫ1 (different from control; P Ͻ 0.10). Hence, E max would change little in steady state in response to a step increase in CVP. Stimulation of the cardiopulmonary baroreflex increases ventricular contractility through ␤-adrenergic receptor system mediation.beat-to-beat variability; cardiopulmonary baroreflex; maximal ventricular elastance; system identification; ventricular contractility THE BAROREFLEX SYSTEMS ARE primarily responsible for maintaining blood pressure in the short term (seconds to minutes) and also appear to contribute to longer-term blood pressure regulation (29,30). It is well known that the arterial baroreflex senses arterial blood pressure (ABP) via stretch receptors lying in the carotid sinus and aortic arch and buffers an increase in ABP by decreasing, for example, total peripheral resistance (TPR), heart rate (HR), and ventricular contractility. The sensory receptors of the cardiopulmonary baroreflex are more complex, residing mainly in the cardiac chambers but also in the pulmonary vessels (5). These receptors have been shown to be responsive to both central venous pressure (CVP) (7,25) and left atrial pressure (LAP) (10, 21), which often change in parallel. The cardiopulmonary baroreflex responds to a change in these pressures by inducing an opposite change in TPR (1,16,25). An increase in the preload pressures also leads to an increase in HR (i.e., Bainbridge effect) in dogs (3), but an opposite change may occur in humans (7).However, the cardiopulmon...

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contrasting

confidence: 57%

mentioning

confidence: 99%

Stimulation of the cardiopulmonary baroreflex enhances ventricular contractility in awake dogs: a mathematical analysis study

Sala‐Mercado

Moslehpour

Hammond

et al. 2014

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Firstly, Furnival, Linden & Snow (1971) showed that the reflex increase in heart rate is unaccompanied by significant reflex inotropic changes in the ventricle, suggesting that only the fibres innervating the sino-atrial node participated in the atrial receptor-heart reflex. Thus the present findings suggest that the efferent fibres participating in the atrial receptor-heart rate reflex are separate from those which effect both reflex responses in heart rate and inotropic state of the ventricle (e.g.…”

Section: Discussionmentioning

confidence: 99%

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

Mary

Weatherill

1982

Exp Physiol

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The reflex increase in activity in efferent cardiac sympathetic nerve fibres in response to distension of small balloons in the pulmonary vein‐atrial junctions was studied in dogs anaesthetized with chloralose; the carotid sinuses were isolated and perfused with blood. In the efferent cardiac nerves which responded to distension of the balloons there was no significant change in the control activity, or in the magnitude of the response during changes in carotid sinus pressure from 8 to 30 kPa, during changes in the blood perfusing the sinuses from arterial to venous or during stimulation of the cutaneous branch of the left radial nerve. In contrast, in efferent cardiac nerves which did not respond to the distension of the balloons, consistent and significant changes in activity resulted from stimulating arterial baroreceptors, chemoreceptors or a cutaneous branch of the radial nerve. It is concluded that efferent cardiac sympathetic nerve fibres which respond by an increase in activity to stimulation of the atrial receptors, constitute a group of nerve fibres which are separate from those responding to stimulation of receptors in the carotid region or to stimulation of peripheral somatic nerves.

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“…Stimulation of left atrial receptors by distension of balloons at the pulmonary vein-atrial junctions was shown to result in a reflex tachycardia which was abolished by blockade of transmission in the sympathetic nerves to the heart (Ledsome & Linden, 1964a, 1968Furnival, Linden & Snow, 1971). More recently Burkhart & Ledsome (1974) have shown that distension of balloons at the pulmonary vein-atrial junctions also resulted in a tachycardia which persisted after section of the cervical spinal cord.…”

Section: Cardiovascular Unit Department Of Physiology University Ofmentioning

confidence: 99%

Communications

1974

The Journal of Physiology

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COMMUNICATIONSPost-tetanic potentiation of isometric twitch tension is not transferred from one motor unit to another in the same small isolated muscle BY G. R. HAMMOND* and R. M. A. P. RIDGE. Department of Physiology, University of BristolIn the course of a study of post-tetanic potentiation (PTP) and depression in single motor units in M. costocutaneus inferioris of snake, we looked for evidence of transfer of potentiation from one unit that had been tetanically stimulated to other units that had not. This evidence was sought because, in order to discuss PTP quantitatively in terms of a model involving intracellular factors, it was necessary to exclude any component of PTP involving extracellular changes, i.e. changes in local ion or metabolite concentration, or in the stress-strain properties of components of the series elastic element common to different units.Excised muscles with a length of segmental and muscle nerve (Hunt & Wylie, 1970) from snakes (Thamnophis and Natrix sp.) were pinned out in an organ bath, superfused with physiological saline controlled to 22 + 0.50 C, and set up for stimulation and isometric tension recording. The muscles were 10-20 mm long, 2-4 mm wide, and usually < 4 fibres thick; and contained tonic and twitch muscle fibres with various contraction times (Ridge, 1971), which ran the full length of the muscle.Responses from single twitch motor units were obtained by a combination of local stimulation and partial section of the segmental nerve, and were analysed on-line with a computer (Modular I, CTL). Their unitary nature was judged by the all-or-none appearance and shape of the isometric tension response and the en passant action potential in the muscle nerve. It was observed that muscle fibres in a unit were distributed throughout the width of the muscle. There were usually < 5 twitch motor units per muscle.The observations reported here were obtained from seven muscles, in each of which two units were isolated and could be stimulated separately. In four of these the experiment consisted of four runs: first, tetanic stimulation of unit 1 followed by twitch-testing of unit 1; second, tetanic stimulation of unit 2 followed by twitch-testing of unit 2; third, tetanic stimulation of unit 1 followed by twitch-testing of unit 2; and fourth, * M.R.C. Scholar. 59P

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Reflex effects on the heart of stimulating left atrial receptors

Cited by 59 publications

References 28 publications

Stimulation of the cardiopulmonary baroreflex enhances ventricular contractility in awake dogs: a mathematical analysis study

Stimulation of the cardiopulmonary baroreflex enhances ventricular contractility in awake dogs: a mathematical analysis study

The Response in Efferent Cardiac Sympathetic Nerves to Stimulation of Atrial Receptors, Carotid Sinus Baroreceptors and Carotid Chemoreceptors

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