Key Points
- To investigate whether irregular burst firing of sympathetic nerves differentially alters contractile responses in isolated rat mesenteric arteries and veins compared to regular stimulation.
- Excised small mesenteric arteries and veins of rats were subjected to electrical field stimulation using recorded physiological human vasoconstrictor patterns.
- Delivered irregular burst sequences at average frequencies of 1.6 Hz and 1.8 Hz alongside continuous, regular frequency stimulation.
- Evaluated frequency-response curves under continuous regular stimulation to determine baseline vessel responsiveness across stimulation rates.
- Arterial contractile responses were significantly greater during irregular burst stimulation than during continuous regular stimulation at matched average frequencies.
- Venous contractions showed similar magnitudes regardless of whether stimuli were delivered in irregular bursts or regular intervals.
- Frequency-response curves showed arteries respond less than veins at lower frequencies, explaining the arterial sensitivity to high-frequency bursts.
Structured PICO
Does irregular electrical field stimulation alter contractile responses compared to regular stimulation in excised rat mesenteric arteries and veins?
PPopulationExcised small mesenteric arteries and veins of the rat
IInterventionElectrical field stimulation delivered in irregular bursts (average frequencies of 1.6 and 1.8 Hz, triggered by human skin vasoconstrictor impulses)
CComparatorElectrical field stimulation delivered at regular intervals
OOutcomeContractile responses (degree of vasoconstriction)surrogate
The normal irregular sympathetic discharge pattern influences the degree of arterial vasoconstriction more than regular stimulation, highlighting the physiological importance of impulse patterns in neuro-effector control.