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Substance P (SP) and neurokinin a (NKA) in developing submandibular glands of the rat
Author(s) -
Virta E.,
Salo A.,
Uusitalo H.
Publication year - 1994
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(94)90039-6
Subject(s) - carbachol , neurokinin a , medicine , endocrinology , isoprenaline , substance p , submandibular gland , chemistry , biology , neuropeptide , receptor , stimulation
The effect of isoprenaline, carbachol, substance P (SP) and neurokinin A (NKA) on peroxidase and total protein secretion was studied in the developing postnatal submandibular glands of the rat using in vitro methods. Submandibular glands of 1, 5, 12 and 30 day‐old‐rats were stimulated by 10 −5 M isoprenaline and carbachol, and 10 −6 M SP and NKA. The stimulatory effects of these compounds were compared to the basic release of peroxidase and total amount of protein from submandibular gland fragments in incubation solution with no added transmitter substances. Indirect immunohistochemical methods were used to study these developing glands from SP‐ and NKA‐immunoreactive (IR) nerve fibers. The distributions of SP‐IR and NKA‐IR nerve fibers closely resembled each other, being most abundantly spread around the developing acini and ducts. The number of these fibers was high on the 1st, 5th and 12th days, but was decreased on the 30th day. On peroxidase release, isoprenaline was the most effective, causing a maximal response of 47 times the basic release on the first postnatal day, after which it gradually decreased. The effects of carbachol, SP and NKA on peroxidase release were clearly weaker and, unlike isoprenaline, their strongest response was on the 5th postnatal day (carbachol, 4.3; SP 5.2; NKA, 4.5). The total protein secretion effect patterns of the studied substances resembled each other more, showing their strongest response on the 5th day (isoprenaline, 5.0; carbachol, 4.5; SP, 4.2; NKA, 3.4) and decreasing thereafter. In general, both the stimulatory pattern of SP and NKA, and the appearance and distribution of SP‐IR and NKA‐IR nerve fibers during the early postnatal period of development closely resemble those of parasympathetic nerves and their transmitters. Furthermore, it is concluded that the abundancy of SP‐IR and NKA‐IR nerves in the developing submandibular gland is accompanied by the increased sensitivity of the secretory elements to these tachykinins, indicating that they play a role in the maturation of the glandular secretory functions.