Neuropeptides and a neuronal marker in cutaneous innervation during human foetal development.
There is evidence that foetal body movements first occur at 6 weeks gestation, and that the reflex arc is functional at 8 weeks. This correlates with the detection of the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP) in spinal cord at 10 weeks gestation. However, the development of cutaneous neuropeptide-containing nerves is not well documented in humans. We have investigated the early appearance and distribution pattern of CGRP, SP, vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), as well as those of the general neuronal marker protein gene product 9.5 (PGP) in various areas of foetal skin at different gestational ages. PGP-immunoreactive nerves were first seen in the subepidermal plexus at 6 weeks gestational age. Initially, the immunoreactive nerves are thick, club-shaped and distributed in the superficial dermis. Beaded adult-like fibres become more numerous only at later ages (10-12 weeks), and extend from this plexus to penetrate the epidermis. Histologically, the skin of the hand develops faster than that of other body areas and at 9 weeks, more PGP-immunoreactive nerves were seen in the palm than in the dorsum. Primitive sweat glands were first noted in axillary skin at 17 weeks, accompanied by a few PGP-immunoreactive nerves. Occasional, small CGRP-immunoreactive fibres were first noticed in the dermis at 7 weeks, but it was at 17 weeks that the presence of this neuropeptide was unequivocal in the subepidermal plexus. Sparse VIP-, SP- and NPY-immunoreactive fibres were not found until 16-17 weeks gestation, when they were seen in the dermis and around small blood vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
Terenghi
G
G
Histochemistry Department, Hammersmith Hospital, London, United Kingdom.
Sundaresan
M
M
Moscoso
G
G
Polak
J M
JM
D015415:Biomarkers; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D005314:Embryonic and Fetal Development; D005333:Fetus / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D009420:Nervous System / Q000196:embryology; D009474:Neurons / Q000378:metabolism*; D009475:Neurons, Afferent / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D012867:Skin / Q000294:innervation*; D013373:Substance P / Q000378:metabolism; D013869:Thiolester Hydrolases / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase
D015415:Biomarkers; D009479:Neuropeptides; D013373:Substance P; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide