Beta-Alanine and Taurine Microinjected into the Rat Caudal Ventrolateral Medulla Increase Blood Pressure

Abstract

Unilateral microinjections of GABA, glycine, β-alanine and taurine into the caudal ventrolateral medulla (CVLM) of the rat, led to an increase in blood pressure and heart rate. The responses to glycine, β-alanine and taurine but not to GABA could be blocked by strychnine. The responses to taurine and β-alanine but not to GABA and glycine could be blocked by 6-aminomethyl-3-methyl-4H-1,2,4-benzothiadiazine-1,1-dioxide (TAG), an antagonist of taurine. The taurine antagonist alone injected bilaterally into the CVLM produced a decrease in blood pressure. From CVLM areas microperfused with Krebs solution, spontaneous release of GABA, glycine, β-alanine and taurine was detected and high K⁺ stimulation caused a calcium-dependent release of GABA, β-alanine and taurine. These results suggest that β-alanine and taurine as well as GABA may be involved in modulation of the cardiovascular control within the CVLM.

Key Words:

• Caudal ventrolateral medulla
• β-Alanine
• Taurine
• Glycine
• Blood pressure
• Rat