Key result
In anaesthetized rats, intravenous noradrenaline infusion produced a dose-dependent increase in mean arterial blood pressure (up to 32%, p<0.001) driven entirely by an increase in cardiac output, with no significant change in total peripheral vascular resistance.
Why the study?
How do adrenoceptor and ganglionic blocking agents modify the cardiovascular response to noradrenaline infusion in anaesthetized rats?
Population
30 male rats of an SPF Wistar derived strain, body weight 420-650 g, anaesthetized with pentobarbitone sodium
Comparison
Intravenous noradrenaline infusion alone or… vs Control conditions
Design
Preclinical
Authors
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Challenges noradrenaline's assumed vasoconstrictor dominance; leaves open translation to conscious humans or clinical practice.
How do adrenoceptor and ganglionic blocking agents modify the cardiovascular response to noradrenaline infusion in anaesthetized rats?
p-value: p=<0.001
In the anaesthetized rat, noradrenaline raises blood pressure solely by increasing cardiac output rather than peripheral resistance, a balance that is unmasked by adrenoceptor blockade.
Imms et al. (1977) studied Healthy (anaesthetized) (n=30). Noradrenaline infusion vs. Baseline (pre-infusion control) was evaluated on Mean arterial blood pressure (MABP) increase at 1500 ng/min (p=<0.001). In anaesthetized rats, intravenous noradrenaline infusion produced a dose-dependent increase in mean arterial blood pressure (up to 32%, p<0.001) driven entirely by an increase in cardiac output, with no significant change in total peripheral vascular resistance.
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