Why the study?
Does phenylephrine alter the automatic discharge rate differently in neonatal versus adult canine cardiac Purkinje fibers?
Population
Isolated neonatal (less than 10 days, n=23) and adult (n=32) canine cardiac Purkinje fibers
Comparison
Superfusion with 5 X 10 M phenylephrine… vs Comparison between neonatal and adult fibers…
Design
Preclinical
Key result
Phenylephrine decreased automatic rate in 75% of adult and 52% of neonatal canine Purkinje fibers, while causing an alpha-adrenergic-induced acceleration in the remaining neonates not seen in adults.
Authors
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Suggests age-dependent differences in alpha-adrenergic receptor function; leaves open whether these developmental.
Does phenylephrine alter the automatic discharge rate differently in neonatal versus adult canine cardiac Purkinje fibers?
Absolute Event Rate: 75% vs 52%
Neonatal canine Purkinje fibers exhibit an alpha-adrenergic-induced acceleration of automatic rate that is not seen in adults, suggesting developmental changes in autonomic receptor function.
Reder et al. (2017) studied Canine cardiac Purkinje fiber automaticity (n=55). Phenylephrine vs. Adult vs Neonatal fibers was evaluated on Decrease in rate of automatic discharge. Phenylephrine decreased automatic rate in 75% of adult and 52% of neonatal canine Purkinje fibers, while causing an alpha-adrenergic-induced acceleration in the remaining neonates not seen in adults.
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