TY - JOUR
T1 - Local cerebral blood flow response to locally infused 2-chloroadenosine during hypotension in piglets
AU - Park, T. S.
AU - Gidday, Jeffrey M.
AU - Gonzales, Ernesto
N1 - Funding Information:
Acknowledgements. This work was supported by NIH Grants NS 00924 and 21045. We thank Mrs. Aarti Shah for technical assistance and Mrs. Joyce Linn for editorial assistance.
PY - 1991/7/16
Y1 - 1991/7/16
N2 - Brain interstitial adenosine increases during hypotension in piglets. If adenosine is to participate in the regulation of neonatal cerebral blood flow (CBF) during hypotension, it must retain its vasodilatory action under that condition. To examine this issue, we studied the effects of locally infused 2-chloroadenosine (2-CADO), a stable adenosine analog, on local CBF in the piglet frontal cortex during normotension and graded hemorrhagic hypotension. We used the modified brain microdialysis/hydrogen clearance technique to simultaneously infuse 2-CADO into the frontal cortex and measure local CBF from the same area. When 2-CADO from 10-8 M to 10-3 M was infused under control conditions (n = 7), CBF increased 61% at 10-5 M, 167% at 10-4 M, and 210% at 10-3 M. In hypotension experiments, local infusion of 10-5 M 2-CADO (n = 8) caused significant increases in CBF (P < 0.05) under control conditions (MABP = 65 mmHg) and at hypotensive blood pressures of 55 mmHg and 44 mmHg, respectively. At a blood pressure of 33 mmHg, however, infusion of the analog failed to increase CBF. Local infusion of 10-3 M 2-CADO also produced a similar change in CBF during graded hypotension. These results indicate that 2-CADO dilates intracerebral vessels during normotension, and mild and moderate hypotension, and support the hypothesis that endogenous adenosine mediates autoregulatory adjustments of CBF during hypotension in newborn piglets.
AB - Brain interstitial adenosine increases during hypotension in piglets. If adenosine is to participate in the regulation of neonatal cerebral blood flow (CBF) during hypotension, it must retain its vasodilatory action under that condition. To examine this issue, we studied the effects of locally infused 2-chloroadenosine (2-CADO), a stable adenosine analog, on local CBF in the piglet frontal cortex during normotension and graded hemorrhagic hypotension. We used the modified brain microdialysis/hydrogen clearance technique to simultaneously infuse 2-CADO into the frontal cortex and measure local CBF from the same area. When 2-CADO from 10-8 M to 10-3 M was infused under control conditions (n = 7), CBF increased 61% at 10-5 M, 167% at 10-4 M, and 210% at 10-3 M. In hypotension experiments, local infusion of 10-5 M 2-CADO (n = 8) caused significant increases in CBF (P < 0.05) under control conditions (MABP = 65 mmHg) and at hypotensive blood pressures of 55 mmHg and 44 mmHg, respectively. At a blood pressure of 33 mmHg, however, infusion of the analog failed to increase CBF. Local infusion of 10-3 M 2-CADO also produced a similar change in CBF during graded hypotension. These results indicate that 2-CADO dilates intracerebral vessels during normotension, and mild and moderate hypotension, and support the hypothesis that endogenous adenosine mediates autoregulatory adjustments of CBF during hypotension in newborn piglets.
KW - 2-Chloroadenosine
KW - Adenosine
KW - Cerebral blood flow
KW - Hypotension
KW - Neonatal pig
UR - http://www.scopus.com/inward/record.url?scp=0025801785&partnerID=8YFLogxK
U2 - 10.1016/0165-3806(91)90115-Y
DO - 10.1016/0165-3806(91)90115-Y
M3 - Article
C2 - 1914158
AN - SCOPUS:0025801785
VL - 61
SP - 73
EP - 77
JO - Developmental Brain Research
JF - Developmental Brain Research
SN - 0165-3806
IS - 1
ER -