Figure 5. Effect of low glucose (1 mM) on the spontaneous (20% O₂) carotid sinus nerve (CSN) activity and on the activity elicited by hypoxia (superfusion with solutions equilibrated with 5% O₂).

A, typical recording of the effect of low glucose (1 mm) on the frequency of action potentials of CSN during superfusion with a solution equilibrated with 5% O₂. In black is shown the control response to hypoxia (5.5 mm glucose) and in grey the effect of hypoglycaemia (1 mm) on the hypoxic response. Both responses were obtained from the same CB and 1 mm of glucose was present in the superfusing solution the 5 min prior to and the 3 min of hypoxic stimulation; the rest of the experiment the superfusing solution contained 5.5 mm glucose. At the top of the figure are shown sample neurograms obtained at the times indicated in A. B–D show, respectively, mean basal frequencies, mean peak frequencies and latencies and times to peak in control (open bars) and in low glucose-treated preparations (filled bars). Data represent means +s.e.m. (n = 7; P < 0.05, two-way ANOVA with Bonferroni's multicomparison test.