Related Experiment Videos
Flow-induced responses in piglet isolated cerebral arteries
L A Shimoda1, N A Norins, D C Jeutter
1Department of Biomedical Engineering, Marquette University, Milwaukee, Wisconsin, USA.
Pediatric Research
|April 1, 1996
Summary
Neonatal cerebral arteries constrict then dilate in response to increasing blood flow, a biphasic reaction mediated by nitric oxide and intracellular calcium. These flow-induced responses depend on endothelial cell deformation.
Area of Science:
- Physiology
- Neuroscience
- Vascular Biology
Background:
- Cerebral hemorrhage is a common neurologic disorder linked to blood flow fluctuations.
- The cerebrovascular response to blood flow in neonates remains poorly understood.
- Understanding neonatal cerebrovascular tone is crucial for managing neurological disorders.
Purpose of the Study:
- To characterize the response of neonatal cerebral arteries to changes in blood flow.
- To elucidate the underlying pathways involved in flow-mediated cerebrovascular tone modulation.
- To investigate the role of endothelial cells in flow-induced vascular responses.
Main Methods:
- Cannulation and perfusion of middle cerebral arteries from piglets (2-14 days old).
- Controlled pressure and flow rate adjustments to generate flow/diameter curves.
- Assessment of vascular responses in modified physiological saline solutions (Na+-reduced, Ca2+-free) and with pharmacological agents (indomethacin, 6-hydroxydopamine, N-nitro-L-arginine methyl ester, N-omega-nitro-L-arginine (NLA), L-arginine, ryanodine, glutaraldehyde).
Main Results:
- Neonatal piglet middle cerebral arteries exhibited a biphasic response to increasing flow: initial constriction followed by dilation.
- Flow-induced constriction was abolished in Na+-reduced and Ca2+-free solutions, suggesting a role for ion transport.
- Dilation was inhibited by N-nitro-L-arginine methyl ester, NLA, and ryanodine, but restored by L-arginine, indicating nitric oxide and intracellular calcium involvement.
- Glutaraldehyde perfusion eliminated both flow-induced constriction and dilation, confirming the critical role of endothelial cell deformation.
Conclusions:
- Neonatal cerebrovascular responses to flow are biphasic and mediated by endothelial mechanisms.
- Nitric oxide and intracellular calcium are key mediators of flow-induced dilation in these arteries.
- Endothelial cell deformation is essential for both constrictive and dilatory responses to blood flow.
- Prostaglandins and adrenergic nerve endings do not appear to play a significant role in these flow-induced responses.