Norepinephrine-induced pulmonary petechiae in the rat: an experimental model with potential implications for sudden...

Autonomic nervous system abnormalities have been implicated in infants dying of or considered at high risk of sudden infant death syndrome (SIDS). In a rat model, norepinephrine (0.02 mg/kg) caused systemic hypertension and numerous pulmonary petechiae, the latter a common finding in SIDS. Petechiae were not seen below the diaphragm. The animals were killed by tracheal occlusion 5 min after the intravenous administration of norepinephrine. The number of pulmonary petechiae was greatly reduced by alpha-adrenergic blockade (phentolamine) and dopaminergic blockade (haloperidol) but not by beta-adrenergic blockade (timolol). A significantly greater reduction of peak mean systemic arterial pressure occurred after alpha-adrenergic blockade than with other blocking agents. It is conceivable that hypoxia-induced endogenous catecholamine release contributes to the pathogenesis of pulmonary petechiae found at necropsy of SIDS victims.