Nonlinearity and fractality in the variability of cardiac period in the lizard, Gallotia galloti: effects of autonomic blockade

2008 ◽  
Vol 295 (4) ◽  
pp. R1282-R1289
Author(s):  
Luis De Vera ◽  
Alejandro Santana ◽  
Julian J. Gonzalez
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Chaotic Behavior ◽  
Autonomic Nervous ◽  
Fractal Properties ◽  
Adrenergic Activity ◽  
Autonomic Blockade ◽  
Cardiac Period ◽  
Over Time ◽  
Gallotia Galloti

Both nonlinear and fractal properties of beat-to-beat R-R interval variability signal (RRV) of freely moving lizards ( Gallotia galloti) were studied in baseline and under autonomic nervous system blockade. Nonlinear techniques allowed us to study the complexity, chaotic behavior, nonlinearity, stationarity, and regularity over time of RRV. Scaling behavior of RRV was studied by means of fractal techniques. The autonomic nervous system blockers used were atropine, propranolol, prazosin, and yohimbine. The nature of RRV was linear in baseline and under β-, α1- and α2-adrenoceptor blockades. Atropine changed the linear nature of RRV to nonlinear and increased its stationarity, regularity and fractality. Propranolol increased the complexity and chaotic behavior, and decreased the stationarity, regularity, and fractality of RRV. Both prazosin and yohimbine did not change any of the nonlinear and fractal properties of RRV. It is suggested that 1) the use of both nonlinear and fractal analysis is an appropriate approach for studying cardiac period variability in reptiles; 2) the cholinergic activity, which seems to make the α1-, α2- and β-adrenergic activity interaction unnecessary, determines the linear behavior in basal RRV; 3) fractality, as well as both RRV regularity and stationarity over time, may result from the balance between cholinergic and β-adrenergic activities opposing actions; 4) β-adrenergic activity may buffer both the complexity and chaotic behavior of RRV, and 5) neither the α1- nor the α2-adrenergic activity seem to be involved in the mediation of either nonlinear or fractal components of RRV.

Consistency and Test-Retest Reliability of Spontaneous Autonomic Nervous System Activity and Eye Movements

1965 ◽  
Vol 20 (3_suppl) ◽  
pp. 1225-1228 ◽  
Author(s):  
Frank E. Hustmyer ◽  
J. Alan Burdick
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Eye Movements ◽  
Autonomic Nervous System Activity ◽  
Retest Reliability ◽  
System Activity ◽  
Autonomic Nervous ◽  
Nervous System Activity ◽  
Test Retest Reliability ◽  
Over Time

Spontaneous autonomic nervous system (ANS) activity (GSR) was recorded during rest, and frequency of horizontal eye movements was recorded during the viewing of two different dot patterns by 14 Ss. The same tasks were repeated after a 2- to 4-mo. period. ANS activity during rest was found to be quite consistent over time ( rho = .75, p < .01) as were eye movements. The within-session rho between eye movements on the patterns was .30 (N.S.) for the first session and .76 ( p < .01) for the second session. The rhos of eye movements obtained 2 to 4 mo. apart were .58 ( p < .05) for a 6-dot stimulus and .77 ( p < .01) for a 1-dot stimulus. When eye movements for the 2 conditions were combined, rho was .78 ( p < .01) between the sessions separated by 2 to 4 mo.

4. Shedding light on the clock

2017 ◽  
pp. 45-61
Author(s):  
Russell G. Foster ◽  
Leon Kreitzman
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Physical Exercise ◽  
Circadian Clock ◽  
Suprachiasmatic Nucleus ◽  
Human Body ◽  
Circadian Clocks ◽  
Autonomic Nervous ◽  
Over Time ◽  
Daily Patterns

Most circadian clocks make use of a sun-based mechanism as the primary entraining signal to lock the internal day to the astronomical day. For nearly four billion years, dawn and dusk has been the main zeitgeber that allows entrainment. Circadian clocks are not exactly 24 hours. So to prevent daily patterns of activity and rest from freerunning over time, light can reset the clock. ‘Shedding light on the clock’ explains that the main circadian clock has been located in the suprachiasmatic nucleus in the hypothalamus. This also regulates the activity of the autonomic nervous system, but there are clocks in virtually every cell in the human body. Other zeitgebers include food, physical exercise, and temperature.

scholarly journals THE UTILITY OF PUPILLARY LIGHT REFLEX AS AN OBJECTIVE BIOMARKER OF ACUTE CONCUSSION IN THE ADOLESCENT ATHLETE

2019 ◽  
Vol 7 (3_suppl) ◽  
pp. 2325967119S0015
Author(s):  
Olivia E. Podolak ◽  
Nabin Joshi ◽  
Kenneth Ciuffreda ◽  
Fairuz Mohamed ◽  
Shelly Sharma ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Pupil Diameter ◽  
Light Stimulus ◽  
Pupillary Light Reflex ◽  
Post Injury ◽  
Light Reflex ◽  
Autonomic Nervous ◽  
Pupillary Light ◽  
Over Time

Background: Visual deficits and autonomic dysfunction have been well recognized following pediatric concussion. Testing of the pupillary light reflex (PLR) is a simple, non-invasive, and objective approach to examine the autonomic nervous system by accessing the brain pathways. The aim of this study was to objectively evaluate adolescent pupillary responses to a light stimulus after a physician-diagnosed concussion and compare them to baseline responses. Methods: In this prospective cohort study, PLR was assessed in 135 adolescent athletes (ages 14-18) during their sport pre-season. All of the athletes were not recovering from a concussion at the time of their baseline assessment. Within this cohort, seven athletes (ages 14-17) sustained a concussion during their sport season and had longitudinal post-injury assessments of PLR through their recovery. The PLR was obtained in response to a brief step-input (0.8 seconds) white light stimulus using a hand-held pupillometer (stimulus recording duration= 5 seconds, light intensity= 150 lux). Pre-set and automated device-generated parameters used for analysis include the minimum and maximum pupil diameter, response amplitude and latency, mean constriction and dilation velocities and the maximum constriction velocity of the eye in response to a light stimulus. During each assessment, three monocular trials were performed in each eye alternatively, and the responses for each eye were subsequently averaged. Results: Six out of the seven concussed adolescents showed response enhancement of about 20% (IQR 11-33%). Enhancement was noted in the steady state diameter with a mean of 24% (median 18%), minimum pupil diameter mean of 17% (median 11%) and maximum constriction velocity mean of 28% (median 33%) following concussion, which decreased during the recovery process (days to weeks post-injury) to pre-injury or below initial pre-injury baseline measurements. Pupillary responsivity was found to be significantly enhanced after concussion compared to baseline measurements, waning over time. Maximum constriction velocity better highlighted the enhancement compared to the baseline pupil diameter. Conclusions/Significance: Pupil responsivity was found to be significantly enhanced after concussion compared to baseline measurements which waned over time during recovery. Assessment of dynamic PLR responses has potential utility as an objective biomarker to aid in concussion diagnosis on the sidelines or in the office, allowing physicians to quantify function (and dysfunction) of the autonomic nervous system under parasympathetic and sympathetic control after concussion.

Atrial natriuretic peptide infusion causes vasoconstriction after autonomic blockade in conscious dogs

1990 ◽  
Vol 259 (4) ◽  
pp. R813-R822 ◽  
Author(s):  
R. L. Woods ◽  
W. P. Anderson
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Vascular Resistance ◽  
Autonomic Nervous ◽  
Autonomic Blockade ◽  
Autonomic Reflex ◽  
Conscious Animals ◽  
Atrial Natriuretic

Many studies have shown that atrial natriuretic peptide (ANP) reduces mean arterial pressure (MAP) in conscious animals by lowering cardiac output (CO) with no change or even increased total peripheral resistance (TPR). Because ANP is thought to be a vasodilator, the lack of fall in TPR in conscious animals is generally considered to be due to autonomic reflex increases in vascular resistance. In the present study in conscious, trained, chronically instrumented dogs (n = 7), we measured hemodynamic and renal excretory responses to 30-min infusions of alpha-human ANP (alpha hANP; 25, 50, and 100 ng.kg-1.min-1) in the presence and absence of autonomic nervous system blockade using the ganglion blocking agent pentolinium. In the absence of blockade, MAP and CO fell, whereas TPR rose with alpha hANP infusions, but these changes did not reach significance. There were significant increases in renal vascular resistance (RVR; 16-25%) and mesenteric vascular resistance (MVR; 14-40%). During autonomic nervous system blockade, alpha hANP caused dose-related reductions in MAP (7-12%), due to falls in CO (13-34%). Remarkably, the absence of autonomic reflex responses exposed substantial dose-related increases in TPR (5-33%). Autonomic blockade did not alter the ANP-induced increases in MVR but did abolish the rises in RVR. In summary, ANP caused vasoconstriction in mesenteric vasculature and substantial vasoconstriction in other nonrenal areas, independent of autonomic reflexes.

Role of the autonomic nervous system, renin–angiotensin system, and arginine vasopressin during the onset and maintenance of ACTH hypertension in sheep

1987 ◽  
Vol 65 (8) ◽  
pp. 1739-1751 ◽  
Author(s):  
Campbell D. Spence ◽  
John P. Coghlan ◽  
Derek A. Denton ◽  
Eric H. Mills ◽  
Mark A. Nelson ◽  
...  
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Arginine Vasopressin ◽  
Pressor Response ◽  
Renin Angiotensin System ◽  
Autonomic Ganglion ◽  
Angiotensin System ◽  
Renin Angiotensin ◽  
Autonomic Nervous ◽  
Autonomic Blockade

The roles of the autonomic nervous system, renin–angiotensin system, and arginine vasopressin (AVP) during the onset of ACTH-induced hypertension were investigated in conscious sheep. Autonomic ganglion blockade or combined adrenergic and cholinergic receptor blockade demonstrated that an intact sympathetic nervous system was not essential for the development or maintenance of the hypertension. Autonomic blockade augmented the pressor response to ACTH, indicating that baroreceptor-mediated reflexes normally operate to suppress the degree of hypertension produced by ACTH. Evidence was obtained suggesting that the renin–angiotensin system and AVP may partially contribute to the maintenance of ACTH hypertension in the presence of autonomic blockade. However, the precise mechanism by which ACTH raises arterial pressure remains to be elucidated.

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