Skip to main content
Fig. 1 | Fluids and Barriers of the CNS

Fig. 1

From: Tachycardia and hypertension enhance tracer efflux from the spinal cord

Fig. 1

Modulation of respiration, blood pressure and heart rate. a–d To test how changes in respiration effect tracer efflux from the spinal cord, rats were allowed to either breathe spontaneously (SB) or were mechanically ventilated (MV). The peak circuit pressures (an indirect measurement of intrathoracic pressure) of MV cohorts were significantly higher than that of SB. Similarly, the trough pressures were more negative in the SB group than the MV controls. b, d SB and MV rats had similar respiratory rates (around 50 breaths/ min). e–h To test the effect of blood pressure on tracer efflux from the spinal cord, phenylephrine infusions were administered to induce hypertension. e, g significantly higher mean arterial pressures (MAP) were achieved following both white and grey matter injection. f, h Significantly higher pulse pressures were achieved in the High MAP cohort compared to the Low MAP controls following injection into the spinal grey matter. i–l To investigate the effects of heart rate on tracer efflux from the spinal cord, tachycardia was achieved by electrically pacing animals to 500 bpm. These animals had heart rates approximately 50% higher than the mechanically ventilated controls, with similar or lower blood pressures compared to the low heart rate controls, demonstrated in j, l. The graphs represent data obtained from animals that received an intraspinal injection of fluorescent ovalbumin (AFO-647) in the grey matter a, b, e, f, i, j and white matter c, d, g, h, k, l Two tailed Student’s t-test, **p < 0.01, ***p < 0.001, ****p < 0.0001. All error bars are expressed as ± SD, n = 10 rats

Back to article page