HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 101/5/1406    most recent 00423.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Rasmussen, P. Articles by Quistorff, B. Search for Related Content PubMed PubMed Citation Articles by Rasmussen, P. Articles by Quistorff, B.

MCA V_mean and the arterial lactate-to-pyruvate ratio correlate during rhythmic handgrip

¹Department of Anesthesia, Copenhagen Muscle Research Center; ²Department of Infectious Diseases, Center of Inflammation and Metabolism, Rigshospitalet; ³Department of Medical Biochemistry and Genetics, University of Copenhagen, Copenhagen, Denmark; and ⁴Cardiovascular Research Institute Amsterdam, Department of Internal Medicine, Academic Medical Center, Amsterdam, the Netherlands

Submitted 11 April 2006 ; accepted in final form 16 June 2006

Regulation of cerebral blood flow during physiological activation including exercise remains unknown but may be related to the arterial lactate-to-pyruvate (L/P) ratio. We evaluated whether an exercise-induced increase in middle cerebral artery mean velocity (MCA V_mean) relates to the arterial L/P ratio at two plasma lactate levels. MCA V_mean was determined by ultrasound Doppler sonography at rest, during 10 min of rhythmic handgrip exercise at 65% of maximal voluntary contraction force, and during 20 min of recovery in seven healthy male volunteers during control and a 15 mmol/l hyperglycemic clamp. Cerebral arteriovenous differences for metabolites were obtained by brachial artery and retrograde jugular venous catheterization. Control resting arterial lactate was 0.78 ± 0.09 mmol/l (mean ± SE) and pyruvate 55.7 ± 12.0 µmol/l (L/P ratio 16.4 ± 1.0) with a corresponding MCA V_mean of 46.7 ± 4.5 cm/s. During rhythmic handgrip the increase in MCA V_mean to 51.2 ± 4.6 cm/s was related to the increased L/P ratio (23.8 ± 2.5; r² = 0.79; P < 0.01). Hyperglycemia increased arterial lactate and pyruvate to 1.9 ± 0.2 mmol/l and 115 ± 4 µmol/l, respectively, but it did not significantly influence the L/P ratio or MCA V_mean at rest or during exercise. Conversely, MCA V_mean did not correlate significantly, neither to the arterial lactate nor to the pyruvate concentrations. These results support that the arterial plasma L/P ratio modulates cerebral blood flow during cerebral activation independently from the plasma glucose concentration.

cerebral blood flow; cerebral activation; exercise; hyperglycemia; transcranial ultrasound Doppler

This article has been cited by other articles:

				N. H. Secher, T. Seifert, and J. J. Van Lieshout Cerebral blood flow and metabolism during exercise: implications for fatigue J Appl Physiol, January 1, 2008; 104(1): 306 - 314. [Abstract] [Full Text] [PDF]

				P. Herrero, C. S. Dence, A. R. Coggan, Z. Kisrieva-Ware, P. Eisenbeis, and R. J. Gropler L-3-11C-Lactate as a PET Tracer of Myocardial Lactate Metabolism: A Feasibility Study J. Nucl. Med., December 1, 2007; 48(12): 2046 - 2055. [Abstract] [Full Text] [PDF]