Biomaterial Database

Catecholamine response to maximal exercise following 16 days of simulated microgravity. 1996

K A Engelke, and V A Convertino

Department of Physiology, University of Florida, Gainesville, USA.

BACKGROUND We tested the hypothesis that the elevated peak heart rate (HR) response to maximal exercise following microgravity exposure is associated with increased plasma levels of catecholamines. METHODS To do this, plasma norepinephrine (NE) and epinephrine (E) were measured in venous blood samples obtained from 7 subjects before and immediately after graded supine cycle exercise to volitional fatigue performed prior to and at the conclusion of 16 d of 6 degrees head-down tilt (HDT). RESULTS Resting HR was increased (p = 0.014) following HDT (56 +/- 3 to 63 +/- 2 bpm), but pre-exercise NE concentration (217 +/- 18 pg.ml-1) was not different (p = 0.224) from that measured before HDT (183 +/- 23 pg.ml-1). Peak exercise HR was greater (p = 0.001) after simulated microgravity exposure compared to pre-HDT (181 +/- 3 bpm vs. 172 +/- 4 bpm). NE measured at volitional fatigue was 64% higher (p = 0.004) after HDT compared to that measured prior to HDT (1337 +/- 181 vs. 2191 +/- 189 pg.ml-1 for pre- and post-HDT, respectively). Plasma E concentration at exhaustion was unchanged by microgravity exposure. CONCLUSIONS Our observation of greater levels of plasma NE and peak exercise HR suggests that sympathetic influences on cardiac chronotropic control may be altered by exposure to prolonged microgravity.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D004837	Epinephrine	The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.	Adrenaline,4-(1-Hydroxy-2-(methylamino)ethyl)-1,2-benzenediol,Adrenaline Acid Tartrate,Adrenaline Bitartrate,Adrenaline Hydrochloride,Epifrin,Epinephrine Acetate,Epinephrine Bitartrate,Epinephrine Hydrochloride,Epinephrine Hydrogen Tartrate,Epitrate,Lyophrin,Medihaler-Epi,Acetate, Epinephrine
D005080	Exercise Test	Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.	Arm Ergometry Test,Bicycle Ergometry Test,Cardiopulmonary Exercise Testing,Exercise Testing,Step Test,Stress Test,Treadmill Test,Cardiopulmonary Exercise Test,EuroFit Tests,Eurofit Test Battery,European Fitness Testing Battery,Fitness Testing,Physical Fitness Testing,Arm Ergometry Tests,Bicycle Ergometry Tests,Cardiopulmonary Exercise Tests,Ergometry Test, Arm,Ergometry Test, Bicycle,Ergometry Tests, Arm,Ergometry Tests, Bicycle,EuroFit Test,Eurofit Test Batteries,Exercise Test, Cardiopulmonary,Exercise Testing, Cardiopulmonary,Exercise Tests,Exercise Tests, Cardiopulmonary,Fitness Testing, Physical,Fitness Testings,Step Tests,Stress Tests,Test Battery, Eurofit,Test, Arm Ergometry,Test, Bicycle Ergometry,Test, Cardiopulmonary Exercise,Test, EuroFit,Test, Exercise,Test, Step,Test, Stress,Test, Treadmill,Testing, Cardiopulmonary Exercise,Testing, Exercise,Testing, Fitness,Testing, Physical Fitness,Tests, Arm Ergometry,Tests, Bicycle Ergometry,Tests, Cardiopulmonary Exercise,Tests, EuroFit,Tests, Exercise,Tests, Step,Tests, Stress,Tests, Treadmill,Treadmill Tests
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D014893	Weightlessness	Condition in which no acceleration, whether due to gravity or any other force, can be detected by an observer within a system. It also means the absence of weight or the absence of the force of gravity acting on a body. Microgravity, gravitational force between 0 and 10 -6 g, is included here. (From NASA Thesaurus, 1988)	Microgravity,Zero Gravity,Gravity, Zero
D015444	Exercise	Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.	Aerobic Exercise,Exercise, Aerobic,Exercise, Isometric,Exercise, Physical,Isometric Exercise,Physical Activity,Acute Exercise,Exercise Training,Activities, Physical,Activity, Physical,Acute Exercises,Aerobic Exercises,Exercise Trainings,Exercise, Acute,Exercises,Exercises, Acute,Exercises, Aerobic,Exercises, Isometric,Exercises, Physical,Isometric Exercises,Physical Activities,Physical Exercise,Physical Exercises,Training, Exercise,Trainings, Exercise