Mechanisms of pain-induced local cerebral blood flow changes in the rat sensory cortex and thalamus

Autor: Tamás Mersich, Benedek Erdos, Emese Szelke, Miklós Palkovits, Zsombor Lacza, Ida E. Tóth, Katalin Komjáti, Péter Sándor
Rok vydání: 2003
Předmět:
Male
medicine.medical_specialty
Potassium Channels
Narcotic Antagonists
Thalamus
Pain
Hemodynamics
Blood Pressure
Stimulation
Vasodilation
Nitric Oxide Synthase Type I
Nitric Oxide
Stereotaxic Techniques
KATP Channels
Physical Stimulation
Internal medicine
Receptors
Adrenergic
beta
Potassium Channel Blockers
medicine
Noxious stimulus
Animals
Sensory cortex
Enzyme Inhibitors
Potassium Channels
Inwardly Rectifying
Rats
Wistar
Molecular Biology
Naloxone
Chemistry
General Neuroscience
Genes
fos
Somatosensory Cortex
Blood flow
Receptors
Adrenergic
alpha
Immunohistochemistry
Sciatic Nerve
Rats
Endocrinology
medicine.anatomical_structure
Cerebral blood flow
Prostaglandin-Endoperoxide Synthases
Cerebrovascular Circulation
ATP-Binding Cassette Transporters
Endorphins
Neurology (clinical)
Blood Gas Analysis
Nitric Oxide Synthase
Neuroscience
Developmental Biology
Zdroj: Brain Research. 960:219-227
ISSN: 0006-8993
DOI: 10.1016/s0006-8993(02)03890-8
Popis: It is a well-known phenomenon that cerebral blood flow is coupled to neural activation induced by non-noxious somatosensory stimulation. However, basic questions related to pain-induced cerebral blood flow changes remain unanswered. In the present study, the sciatic nerve of anesthetized rats was subjected to electric stimulation with noxious and non-noxious parameters. Changes in local cerebral blood flow and neuronal activity were determined simultaneously in the sensory cortex and in the thalamus by laser-Doppler flowmetry and c-fos immunohistochemistry, respectively. The role of different vasoregulatory mechanisms and the pain-induced increase in mean arterial blood pressure (MABP) were examined with specific blocking agents and by means of rapid intra-arterial transfusion. Noxious stimulation resulted in significant enhancement of neuronal activity both in the thalamus and in the somatosensory cortex indicated by marked c-fos expression in these areas. Cortical and thalamic blood flow (cBF and tBF) increased by 47+/-4 and 44+/-3% during the stimulation while the MABP elevated by 35+/-2%. Similar changes in MABP induced by intra-arterial transfusion had no effect on tBF, while cBF increased only by 18+/-5%. Blockade of ATP sensitive potassium channels (K(+)(ATP)) and sympathetic beta-receptors significantly attenuated the pain-induced blood flow increases in both investigated areas, while inhibition of nitric oxide synthase was effective only in the thalamus. The blockade of the sympathetic alpha-receptors, opiate receptors, and the cyclooxygenase enzyme had no effect on the pain-induced cerebral blood flow elevations. These findings demonstrate that during noxious stimulation, cerebral blood flow is adjusted to the increased neural activity by the interaction of vasoconstrictor autoregulatory and specific vasodilator mechanisms, involving the activation of sympathetic beta-receptors, K(+)(ATP)-channels and the release of nitric oxide.
Databáze: OpenAIRE
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