Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Zarzeczny, R; Langfort, J; Pilis, W; Nazar, K; Kaciuba-Uscilko, H; Porta, S.
Effect of sustained adrenergic receptors stimulation and blockade on lactate threshold in rats.
J Sports Med Phys Fitness. 2001; 41(3):324-329
Web of Science
PubMed
- Co-Autor*innen der Med Uni Graz
- Porta Sepp
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- Abstract:
- BACKGROUND: This study examined the hypothesis that prolonged (12 hrs) stimulation of adrenergic receptors by adrenaline and their blockade by regitine (alpha-blockade) or propranolol (beta-blockade) affect lactate thresh-old (T(LA)) and exercise tolerance in rats. METHODS: Twenty-four untrained male Wistar rats performed a multistage running test on a treadmill with an intensity increased from 13 m/min to the maximum speed. After a control exercise test the animals were devided into three groups implanted s.c. with: 1) adrenaline; 2) propranolol and 3) regitine tablets. Twelve hours after the tablet implantation the exercise was repeated. Both before the exercise test and at the end of each 2-min loads blood lactate [LA] was measured to evaluate T(LA). RESULTS: Prolonged adrenaline excess resulted in reduced maximal running speed and shifted T(LA) towards lower exercise intensities than in the control test. Both alpha- and beta-adrenergic blockade reduced the work load at which T(LA) occurred, without changing the maximum running speed and maximal blood LA concentration. Blood [LA] at the lactate threshold ([LA] at T(LA)) was significantly higher in hyperadrenalinemic than in control rats, whilst under beta-blockade it was lowered in comparison with control values. Alpha-adrenergic blockade had no effect on [LA] at T(LA), but at the higher exercise intensities blood [LA] exceeded the respective control values. CONCLUSIONS: The present study demonstrated that prolonged excess of adrenaline reduces the maximum power output and T(LA). The former effect seems to be a result of simultaneous stimulation of both types of adrenergic receptors.
- Find related publications in this database (using NLM MeSH Indexing)
- Adrenergic Agonists - pharmacology
- Adrenergic Antagonists - pharmacology
- Animals - pharmacology
- Drug Implants - pharmacology
- Epinephrine - pharmacology
- Exercise Tolerance - drug effects
- Lactates - blood
- Male - blood
- Phentolamine - pharmacology
- Propranolol - pharmacology
- Rats - pharmacology
- Rats, Wistar - pharmacology
- Receptors, Adrenergic - physiology
- Running - physiology
- Find related publications in this database (Keywords)
- exercise
- physiology
- epinephrine
- blood
- receptor adrenergic
- propranolol
- regitine
- lactic acid blood