Purpose We investigated the effect of handgrip (HG) maneuver on time-varying estimates of dynamic cerebral autoregulation (CA) using the autoregressive moving average technique. Methods Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO2 pressure (PETCO2), and noninvasive arterial blood pressure (ABP) were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP), resistance area-product (RAP), and time-varying autoregulation index (ARI) were obtained. Results PETCO2 did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005), which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. Conclusion Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism.
References
[1]
Ainslie PN, Smith KJ (2011) Integrated human physiology: breathing, blood pressure and blood flow to the brain. J Physiol 589: 2917.
[2]
Azevedo E, Castro P, Santos R, Freitas J, Coelho T, et al. (2011) Autonomic dysfunction affects cerebral neurovascular coupling. Clin Auton Res 21: 395–403.
[3]
Stanimirovic D, Friedman A (2012) Pathophysiology of the neurovascular unit: disease cause or consequence? J Cereb Blood Flow Metab 32: 1207–1221.
[4]
Kleinfeld D, Blinder P, Drew P, Driscoll J, Muller A, et al. (2011) A guide to delineate the logic of neurovascular signaling in the brain. Front Neuroenergetics 3: 1–9.
[5]
Aoi M, Hu K, Lo MT, Selim M, Olufsen M, et al. (2012) Impaired Cerebral Autoregulation Is Associated with Brain Atrophy and Worse Functional Status in Chronic Ischemic Stroke. PLoS ONE 7: e46794.
[6]
Krzemijski K, Cybulski G, Ziemba A, Nazar K (2012) Cardiovascular and hormonal response to static handgrip in young and older healthy men. Eur J Appl Physiol 1315–1325.
[7]
Jorgensen L, Perko M, Hanel B, Schroeder T, Secher N (1992) Middle cerebral artery flow velocity and blood flow during exercise and muscle ischemia in humans. J Appl Physiol 72: 1123–1132.
[8]
Rasmussen P, Plomgaard P, Krogh-Madsen R, Kim Y, van Lieshout J, et al. (2006) MCA Vmean and the arterial lactate-to-pyruvate ratio correlate during rhythmic handgrip. J Appl Physiol 101: 1406–1411.
[9]
Sander M, Macefield V, Henderson L (2010) Cortical and brain stem changes in neural activity during static handgrip and postexercise ischemia in humans. J Appl Physiol 108: 1691–1700.
[10]
Kim Y, Krogh-Madsen R, Rasmussen P, Plomgaard P, Ogoh S, et al. (2007) Effects of hyperglycemia on the cerebrovascular response to rhythmic handgrip exercise. Am J Physiol Heart Circ Physiol 293: H467–473.
[11]
Dawson S, Blake M, Panerai R, Potter J (2000) Dynamic but not static cerebral autoregulation is impaired in acute ischaemic stroke. Cerebrovasc Dis 10: 126–132.
[12]
Eames P, Blake M, Panerai R, Potter J (2003) Cerebral autoregulation indices are unimpaired by hypertension in middle aged and older people. Am J Hypertens 16: 746–753.
[13]
Ogoh S, Ainslie P (2009) Cerebral blood flow during exercise: mechanisms of regulation. J Appl Physiol 107: 1370–1380.
[14]
Ogoh S, Brothers R, Jeschke M, Secher N, Raven P (2010) Estimation of cerebral vascular tone during exercise; evaluation by critical closure pressure in humans. Exp Physiol 95: 678–685.
[15]
Panerai R, Dawson S, Eames P, Potter J (2001) Cerebral blood flow velocity response to induced and spontaneous sudden changes in arterial blood pressure. Am J Physiol Heart Circ Physiol 280: H2162–2174.
[16]
Dineen N, Brodie F, Robinson T, Panerai R (2010) Continuous estimates of dynamic cerebral autoregulation during transient hypocapnia and hypercapnia. J Appl Physiol 108: 604–613.
Panerai R (2003) The critical closing pressure of the cerebral circulation. Med Eng Phys 25: 621–632.
[19]
Tiecks F, Lam A, Aaslid R, Newell D (1995) Comparison of static and dynamic cerebral autoregulation measurements. Stroke 26: 1014–1019.
[20]
Panerai RB, Salinet AS, Brodie FG, Robinson TG (2011) The influence of calculation method on estimates of cerebral critical closing pressure. Physiol Meas 32: 467–482.
[21]
Panerai R, Eyre M, Potter J (2012) Multivariate modelling of cognitive-motor stimulation on neurovascular coupling: Transcranial Doppler used to characterize myogenic and metabolic influences. Am J Physiol Regul Integr Comp Physiol 303: R395–407.
[22]
Carey B, Eames P, Panerai R, Potter J (2001) Carbon dioxide, critical closing pressure and cerebral haemodynamics prior to vasovagal syncope in humans. Clin Sci (Lond) 101: 351–358.
[23]
Edwards M, Schondorf R (2003) Is cerebrovascular autoregulation impaired during neurally-mediated syncope? Clin Auton Res 13: 306–309.
[24]
Ogoh S, Sato K, Akimoto T, Oue A, Hirasawa A, et al. (2010) Dynamic cerebral autoregulation during and after handgrip exercise in humans. J Appl Physiol 108: 1701–1705.
[25]
Paulson O, Hasselbalch S, Rostrup E, Knudsen G, Pelligrino D (2010) Cerebral blood flow response to functional activation. J Cereb Blood Flow Metab 30: 2–14.
[26]
Nowak M, Holm S, Biering-S？rensen F, Secher N, Friberg L (2005) “Central command” and insular activation during attempted foot lifting in paraplegic humans. Hum Brain Mapp 25: 259–265.
[27]
Panerai R, Sammons E, Smith S, Rathbone W, Bentley S, et al. (2008) Continuous estimates of dynamic cerebral autoregulation: influence of non-invasive arterial blood pressure measurements. Physiol Meas 29: 497–513.
[28]
Panerai R, Dineen N, Brodie F, Robinson T (2010) Spontaneous fluctuations in cerebral blood flow regulation: contribution of PaCO2. J Appl Physiol 109: 1860–1868.
[29]
Nakagawa K, Serrador J, Larou S, Moslehi F, Lipsitz L, et al. (2009) Autoregulation in posterior circulation is altered by the metabolic state of the visual cortex. Stroke 40: 2062–2067.
[30]
Panerai RB (2009) Transcranial Doppler for evaluation of cerebral autoregulation. Clin Auton Res 19: 197–211.
[31]
Serrador J, Picot P, Rutt B, Shoemaker J, Bondar R (2000) MRI measures of middle cerebral artery diameter in conscious humans during simulated orthostasis. Stroke 31: 1672–1678.
[32]
Giller C, Giller A, Cooper C, Hatab M (2000) Evaluation of the cerebral hemodynamic response to rhythmic handgrip. J Appl Physiol 88: 2205–2213.
[33]
Ogoh S, Fisher J, Young C, Fadel P (2011) Impact of age on critical closing pressure of the cerebral circulation during dynamic exercise in humans. Exp Physiol 96: 417–425.
