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Responses to antidromic trigeminal nerve stimulation, substance P, NKA, CGRP and capsaicin in the rat eye

Andersson, Sven LU (1987) In Acta Physiologica Scandinavica 131(3). p.371-376
Abstract
In the rat eye, intracameral injections of substance P in doses of 10-30 pmol caused a maximal long-lasting miosis and a leakage of plasma proteins into the aqueous humor, indicating a breakdown of the blood-aqueous barrier. Neurokinin A seemed equipotent to SP, but calcitonin-gene-related peptide (CGRP) (17 pmol) caused neither miosis nor protein leakage into the aqueous humor. The same result was obtained when CGRP was administered intravenously. Intracameral injection of capsaicin caused only a transient miosis which could not be repeated with further injections, even though the pupillary sphincter was still able to react to exogenous SP. Antidromic electrical stimulation of the trigeminal nerve caused plasma extravasation in the skin... (More)
In the rat eye, intracameral injections of substance P in doses of 10-30 pmol caused a maximal long-lasting miosis and a leakage of plasma proteins into the aqueous humor, indicating a breakdown of the blood-aqueous barrier. Neurokinin A seemed equipotent to SP, but calcitonin-gene-related peptide (CGRP) (17 pmol) caused neither miosis nor protein leakage into the aqueous humor. The same result was obtained when CGRP was administered intravenously. Intracameral injection of capsaicin caused only a transient miosis which could not be repeated with further injections, even though the pupillary sphincter was still able to react to exogenous SP. Antidromic electrical stimulation of the trigeminal nerve caused plasma extravasation in the skin and a breakdown of the blood-aqueous barrier with an increased protein content in the aqueous humor. The stimulation did not affect the pupil size. The results indicate that in rat eyes SP and NKA are miotics, but the amounts that can be released from sensory nerve endings are too small to cause persistent miosis. These peptides are more likely to play a role in the neurogenic breakdown of the blood-aqueous barrier. CGRP at the same dose affects neither the pupillary sphincter muscle nor the barrier. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Acta Physiologica Scandinavica
volume
131
issue
3
pages
371 - 376
publisher
Wiley-Blackwell
external identifiers
  • pmid:2447747
  • scopus:0023555584
ISSN
0001-6772
language
English
LU publication?
no
id
85861040-080f-4ade-b789-dd79030f5840 (old id 1104023)
date added to LUP
2008-08-08 17:48:10
date last changed
2017-07-30 04:39:02
@article{85861040-080f-4ade-b789-dd79030f5840,
  abstract     = {In the rat eye, intracameral injections of substance P in doses of 10-30 pmol caused a maximal long-lasting miosis and a leakage of plasma proteins into the aqueous humor, indicating a breakdown of the blood-aqueous barrier. Neurokinin A seemed equipotent to SP, but calcitonin-gene-related peptide (CGRP) (17 pmol) caused neither miosis nor protein leakage into the aqueous humor. The same result was obtained when CGRP was administered intravenously. Intracameral injection of capsaicin caused only a transient miosis which could not be repeated with further injections, even though the pupillary sphincter was still able to react to exogenous SP. Antidromic electrical stimulation of the trigeminal nerve caused plasma extravasation in the skin and a breakdown of the blood-aqueous barrier with an increased protein content in the aqueous humor. The stimulation did not affect the pupil size. The results indicate that in rat eyes SP and NKA are miotics, but the amounts that can be released from sensory nerve endings are too small to cause persistent miosis. These peptides are more likely to play a role in the neurogenic breakdown of the blood-aqueous barrier. CGRP at the same dose affects neither the pupillary sphincter muscle nor the barrier.},
  author       = {Andersson, Sven},
  issn         = {0001-6772},
  language     = {eng},
  number       = {3},
  pages        = {371--376},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Physiologica Scandinavica},
  title        = {Responses to antidromic trigeminal nerve stimulation, substance P, NKA, CGRP and capsaicin in the rat eye},
  volume       = {131},
  year         = {1987},
}