Relation between expression of the peptides and their
receptors.
CGRP and CT were found to be co-expressed in small to medium sized
neurons, and in some SGCs, suggesting that CT might have a role in
trigeminal function (Edvinsson, Grell & Warfvinge, 2020). CGRP and AMY
are co-expressed in some of the small to medium sized neurons and in
thin C-fibres. The number of CGRP positive cells were in abundance
compared to those storing AMY (Edvinsson, Grell & Warfvinge, 2020). AMY
is present in high concentrations in plasma, in migraine attacks higher
levels of CGRP is released than AMY. Since the CGRP receptor is more
sensitive to CGRP than to AMY, AMY is unlikely to have a central role in
migraine.
The CGRP receptor (CLR/RAMP1) is mainly expressed in large neurons and
SGCs (Edvinsson, Grell & Warfvinge, 2020). The AM2receptor (CLR/RAMP3) occurs in some SGCs, the AMY1receptor (CTR/RAMP1) in large neurons and SGCs, while the
AMY3 receptor (CTR/RAMP3) has been observed in some
SGCs.