Oxytocin, which has access to cerebral blood vessels from several sources, may be an important component of cerebrovascular control in newborns. We examined the effects of total global ischemia on pial arteriolar dilator responses to oxytocin in anesthetized newborn piglets. Arteriolar responses to 10-8 and 10-6 M of oxytocin were determined before and 1 hr following a 10 min period of global cerebral ischemia Ischemia was achieved by increasing intracranial pressure and was confirmed visually by cessation of cortical blood flow. Prior to ischemia, oxytocin dilated pial arterioles by 8±2% at 10-8 and by 18±4% at 10-6 M (n=6, P<0.05). One hour after ischemia, oxytocin did not cause dilation at either dose (2±2%, at 10-8 and -3±2 % at 10-6). For the time control animals arteriolar dilation to oxytocin did not change with repeated application (8±2%, 14±5% at the first application, and 9±3% and 14±4% 1 hr later, n=4). We conclude that the absence of pial arteriolar dilation to oxytocin after ischemia may be involved in the pathomechanism of perinatal brain injury. Supported by NIH grants: HL-30260, HL-46558, and HL-50587.
|Publication status||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology