Are muscarinic receptors present in rat pial or intracerebral vessels?
Experiments were performed to determine whether muscarinic receptors were present within rat pial or intracerebral vessels. Localization of muscarinic receptors was determined by autoradiography using [3H]-quinuclidinyl benzilate ([3H]-QNB) as a ligand on brain sections of the frontoparietal and the temporal cortex, the neostriatum and the hippocampus. [3H]-QNB was bound specifically to sections of rat brain in a manner consistent with the labelling of muscarinic receptors. A high density of muscarinic receptors was found primarily in the neostriatum, followed, in descending order, by the cerebral cortex and the hippocampus. However, no specific [3H]-QNB binding was observed at the level of either the pial or intraparenchymal vessels. On the basis of the present data, the existence of muscarinic receptors within rat pial arteries and arterioles, as well as within intracerebral vessels, seems to be highly questionable.
de Michele
M
M
Dipartimento di Scienze Neurologiche, Università La Sapienza, Roma, Italy.
Cavallotti
C
C
Felici
L
L
Ricci
A
A
Amenta
F
F
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D001345:Autoradiography; D002550:Cerebral Veins / Q000378:metabolism; D002560:Cerebrovascular Circulation; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate