Boi, Marianna

Cianchetti, Carlo

Cruz, Francisco

Del Fiacco, Marina

Melis, Tiziana

Quartu, Marina

Serra, Maria Pina

Shevel, Elliot

Firenze University Press: E-Journals

IJAE Vol. 115, n. 1/2 (Supplement), 2010
48
Transient receptor potential vanilloid type-1 (TRPV1) 
in the human trigeminal system and arteries of the scalp
Marina Del Fiacco1, Maria Pina Serra1, Marina Quartu1, Marianna Boi1, Francisco Cruz2, Tiziana Melis1, 
Carlo Cianchetti3, Elliot Shevel4
1 Department of Cytomorphology, University of Cagliari, Italy
2 Faculty of Medicine, University of Porto, Portugal
3 Clinic of Child and Adolescent Neuropsychiatry,University of Cagliari, Italy
4 The Headache Clinic, Parktown, 2193 Johannesburg, South Africa
The non selective cation channel transient receptor potential vanilloid type-1 (TRPV1) 
is expressed by sensory neurons and triggered by a wide variety of activating factors, 
with depolarisation leading to burning pain. TRPV1 activation also leads to release of 
sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) 
which, in turn, activate their effector cell receptors and contribute to the process of neu-
rogenic inflammation and sensitization of nociceptors. In view of the possible involve-
ment of TRPV1 in headache disorders, we undertook the analysis of the occurrence of 
TRPV1 in the trigeminal sensory system and here relate on the localization of TRPV1 im-
munoreactivity in the human scalp arteries and trigeminal ganglion and spinal nucleus, 
and compare it to the distribution of CGRP and SP.
Surgical specimens of temporal, frontal and occipital arteries and autoptic specimens 
of trigeminal ganglion and caudal brainstem were fixed in 4% phosphate buffered para-
phormaldehyde and processed for avidine-biotin-peroxidase complex (ABC) or fluores-
cence immunohistochemistry. 
Arteries of the scalp showed a consistent TRPV1-like immunoreactivity (LI) in form 
of varicose nerve fibres running at the media-adventitia border. In the trigeminal gan-
glion, a subpopulation of predominantly small- to medium-sized neurons showed a 
distinct TRPV1-LI in the perikaryon, sometimes extending to the proximal process. 
Coexistence with CGRP-LI was observed sporadically, whereas coexistence with SP-LI 
was never detected. Centrally, TRPV1-LI labelled extensive fiber tracts and punctate 
terminal-like elements distributed in the spinal tract and in lamina I, inner lamina II 
and deep magnocellular part of the spinal trigeminal nucleus. Neuronal cell bodies with 
membrane-like immunostaining were also detectable in the superficial layers of the nu-
cleus. While TRPV1-LI was widely codistributed with both SP-LI and CGRP-LI, no colo-
calization was detectable in double immunostaining with SP-LI. The results obtained 
will be discussed and compared to the available data in literature.


Transient receptor potential vanilloid type-1 (TRPV1) in the human trigeminal system and arteries of the scalp

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Transient receptor potential vanilloid type-1 (TRPV1) in the human trigeminal system and arteries of the scalp

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