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Temporo‐spatial Expression of the Inducible Nos‐isoform During Development of the Murine Enteric Nervous System
Author(s) -
Arnhold S.,
Andressen C.,
Addicks K.
Publication year - 2005
Publication title -
anatomia, histologia, embryologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.34
H-Index - 35
eISSN - 1439-0264
pISSN - 0340-2096
DOI - 10.1111/j.1439-0264.2005.00669_9.x
Subject(s) - enteric nervous system , myenteric plexus , gene isoform , nitric oxide synthase , biology , nitric oxide , nervous system , medicine , messenger rna , submucous plexus , autonomic nervous system , immunohistochemistry , endocrinology , cholinergic , neuroscience , immunology , biochemistry , gene , heart rate , blood pressure
In the enteric nervous system, nitric oxide (NO) is regarded as an important messenger for the non‐adrenergic and non‐cholinergic neurotransmission. Synthesized mainly by the constitutive nitric oxide synthase (NOS) isoforms NOS I and NOS III, this molecule executes pre‐junctional inhibitory effects in the submucosal plexus as well as relaxation of the enteric smooth muscles. In order to elucidate the role for NO during enteric development, we looked for the expression of all three NOS‐isoforms in the enteric nervous system during mouse development from E8 to E20 using immunohistochemistry. Starting around midgestation, a transient expression of the NOS‐II isoform during the very early development of enteric neurones was detected in parallel to that of HNK‐1 exclusively in the myenteric plexus. Similar to findings for other neuronal systems, NOS‐I and NOS III isoforms could be traced starting significantly later to increase towards the end of embryonic development when NOS II immunoreactivity faded and a strong expression of the vasointestinal peptide (VIP) could be detected. In contrast to the NOSII expression, the constitutive isoforms can also be detected in the submucosal plexus. Altogether, these findings suggest NOS‐II to be exclusively involved during early steps of enteric nervous system development. Absence of downstream signalling elements, such as sGC and cGMP both in neurons and in enteric muscle until the end of the second third of gestation, may indicate different effects executed by NO during development, expressed by Ca 2+ dependent and independent NOS isoforms.