Assessment of the in Vivo Recording of Local Cerebral Blood Flow Using a Thermistor Device

Amylin and adrenomedullin are two peptides structurally related to calcitonin gene-related peptide (CGRP). We studied the occurrence of amylin in trigeminal ganglia and cerebral blood vessels of the cat with immunocytochemistry and evaluated the role of amylin and adrenomedullin in the cerebral circulation by in vitro and in vivo pharmacology. Immunocytochemistry revealed that numerous nerve cell bodies in the trigeminal ganglion contained CGRP immunoreactivity (-ir); some of these also expressed amylin-ir but none adrenomedullin-ir. There were numerous nerve fibres surrounding cerebral blood vessels that contained CGRP-ir. Occasional fibres contained amylin-ir while we observed no adrenomedullin-ir in the vessel walls. With RT-PCR and Real-Time�PCR we revealed the presence of mRNA for calcitonin receptor-like receptor (CLRL) and receptor-activity-modifying proteins (RAMPs) in cat cerebral arteries. In vitro studies revealed that amylin, adrenomedullin, and CGRP relaxed ring segments of the cat middle cerebral artery. CGRP and amylin caused concentration-dependent relaxations at low concentrations of PGF2a-precontracted segment (with or without endothelium) whereas only at high concentration did adrenomedullin cause relaxation. CGRP8-37 blocked the CGRP and amylin induced relaxations in a parallel fashion. In vivo studies of amylin, adrenomedullin, and CGRP showed a brisk reproducible increase in local cerebral blood flow as examined using laser Doppler flowmetry applied to the cerebral cortex of the a-chloralose�anesthetized cat. The responses to amylin and CGRP were blocked by CGRP8-37. The studies suggest that there is a functional sub-set of amylin-containing trigeminal neurons which probably act via CGRP receptors.

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Emission tomographic measurement of local cerebral blood flow in humans by an in vivo autoradiographic strategy

Annals of Neurology ◽

10.1002/ana.410150704 ◽

1984 ◽

Vol 15 (S1) ◽

pp. 12-18 ◽

Cited By ~ 17

Author(s):

Myron D. Ginsberg ◽

Bernard E. Howard ◽

William R. Hassel

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Local Cerebral Blood Flow ◽

Tomographic Measurement

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Effects of Neuropeptide Y and Calcitonin Gene-Related Peptide on Local Cerebral Blood Flow in Rat Striatum

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1989.44 ◽

1989 ◽

Vol 9 (3) ◽

pp. 268-270 ◽

Cited By ~ 33

Author(s):

Yoshio Suzuki ◽

Shin-Ichi Satoh ◽

Ichiro Ikegaki ◽

Tomohisa Okada ◽

Masato Shibuya ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Neuropeptide Y ◽

Calcitonin Gene Related Peptide ◽

Nerve Fibers ◽

Rat Striatum ◽

Local Cerebral Blood Flow ◽

Related Peptide ◽

Calcitonin Gene

The effects of neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) on local cerebral blood flow (LCBF) were studied in vivo in rat striatum. Administration of 1 and 5 nmol NPY as a bolus into the internal carotid artery caused a dose-dependent decrease in the ipsilateral striatal LCBF. This decrease developed slowly and persisted for at least 2 h, without affecting mean blood pressure. In contrast, CGRP, at a concentration of 10 pmol, increased striatal LCBF by about 30%, and the duration of the increase was about 1 h. However, at higher doses of CGRP no increase in LCBF was observed. These results suggest that NPY and CGRP released from nerve fibers innervating blood vessels can function as long-acting modulators of CBF.

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