beta-Alanine

Journal of Physiology, 2010, 539(Pt 1):191-200.

Beta-alanine and taurine as endogenous agonists at glycine receptors in rat hippocampus in vitro.[Pubmed: 11850512]

Electrophysiological and pharmacological properties of glycine receptors were characterized in hippocampal organotypic slice cultures.
METHODS AND RESULTS:
In the presence of ionotropic glutamate and GABA(B) receptor antagonists, pressure-application of glycine onto CA3 pyramidal cells induced a current associated with increased chloride conductance, which was inhibited by strychnine. Similar chloride currents could also be induced with beta-Alanine or taurine. Whole-cell glycine responses were significantly greater in CA3 pyramidal cells than in CA1 pyramidal cells and dentate granule cells, while responses to GABA were similar among these three cell types. Although these results demonstrate the presence of functional glycine receptors in the hippocampus, no evidence for their activation during synaptic stimulation was found. Gabazine, a selective GABA(A) receptor antagonist, totally blocked evoked IPSCs in CA3 pyramidal cells. Glycine receptor activation is not dependent on transporter-controlled levels of extracellular glycine, as no chloride current was observed in response to sarcosine, an inhibitor of glycine transporters. In contrast, application of guanidinoethanesulfonic acid, an uptake inhibitor of beta-Alanine and taurine, induced strychnine-sensitive chloride current in the presence of gabazine.
CONCLUSIONS:
These data indicate that modulation of transporters for the endogenous amino acids, beta-Alanine and taurine, can regulate tonic activation of glycine receptors, which may function in maintenance of inhibitory tone in the hippocampus.

Medicine & ence in Sports & Exercise, 2009, 41(4):898-903.

Beta-alanine improves sprint performance in endurance cycling[Pubmed: 19276843]

Recent research has shown that chronic dietary beta-Alanine (betaALA) supplementation increases muscle carnosine content, which is associated with better performance in short (1-2 min) maximal exercise. Success in endurance competitions often depends on a final sprint. However, whether betaALA can be ergogenic in sprint performance at the end of an endurance competition is at present unknown. Therefore, we investigated the effect of 8-wk betaALA administration in moderately to well-trained cyclists on sprint performance at the end of a simulated endurance cycling race.
METHODS AND RESULTS:
A double-blind study was performed, which consisted of two experimental test sessions interspersed by an 8-wk betaALA (2-4 g.d; n = 9) or matched placebo (PL; n = 8) supplementation period. In the pretesting and the posttesting, subjects performed a 10-min time trial and a 30-s isokinetic sprint (100 rpm) after a 110-min simulated cycling race. Capillary blood samples were collected for determination of blood lactate concentration and pH. Mean power output during the time trial was approximately 300 W and was similar between PL and betaALA during either the pretesting or the posttesting. However, compared with PL, during the final sprint after the time trial, betaALA on average increased peak power output by 11.4% (95% confidence interval = +7.8 to +14.9%, P = 0.0001), whereas mean power output increased by 5.0% (95% confidence interval = +2.0 to +8.1%, P = 0.005). Blood lactate and pH values were similar between groups at any time.
CONCLUSIONS:
Oral betaALA supplementation can significantly enhance sprint performance at the end of an exhaustive endurance exercise bout.

Journal of Applied Physiology, 2007, 103(5):1736-1743.

beta-Alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters.[Pubmed: 17690198]

Carnosine (beta-alanyl-l-histidine) is present in high concentrations in human skeletal muscle. The ingestion of beta-Alanine, the rate-limiting precursor of carnosine, has been shown to elevate the muscle carnosine content.
METHODS AND RESULTS:
We aimed to investigate, using proton magnetic resonance spectroscopy (proton MRS), whether oral supplementation with beta-Alanine during 4 wk would elevate the calf muscle carnosine content and affect exercise performance in 400-m sprint-trained competitive athletes. Fifteen male athletes participated in a placebo-controlled, double-blind study and were supplemented orally for 4 wk with either 4.8 g/day beta-Alanine or placebo. Muscle carnosine concentration was quantified in soleus and gastrocnemius by proton MRS. Performance was evaluated by isokinetic testing during five bouts of 30 maximal voluntary knee extensions, by endurance during isometric contraction at 45% maximal voluntary contraction, and by the indoor 400-m running time. beta-Alanine supplementation significantly increased the carnosine content in both the soleus (+47%) and gastrocnemius (+37%). In placebo, carnosine remained stable in soleus, while a small and significant increase of +16% occurred in gastrocnemius. Dynamic knee extension torque during the fourth and fifth bout was significantly improved with beta-Alanine but not with placebo. Isometric endurance and 400-m race time were not affected by treatment.
CONCLUSIONS:
In conclusion, 1) proton MRS can be used to noninvasively quantify human muscle carnosine content; 2) muscle carnosine is increased by oral beta-Alanine supplementation in sprint-trained athletes; 3) carnosine loading slightly but significantly attenuated fatigue in repeated bouts of exhaustive dynamic contractions; and 4) the increase in muscle carnosine did not improve isometric endurance or 400-m race time.