A, Typical heart rate recordings after microinjection of saline, L-glutamate (L-Glu, 5 mM, 50 nL), BK (20 nM, 50 nL), B1 receptor blocker, R715 (2 µM, 50 nL) alone, or in combination with BK (20 nM, 50 nL), B2 antagonist HOE140 (200 nM, 50 nL) alone or in combination with BK (20 nM, 50 nL). B, Quantifications of the heart rate changes induced by the treatments mentioned in A; n = 6 rats for each condition. *P < 0.05 when compared with the effect of BK; NS, not significant.