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Modulation by thyroid hormones of rat parotid amylase secretion stimulated by 5‐hydroxytryptamine
Author(s) -
Ostuni Mariano Aníbal,
Houssay Alberto Bernardo,
Tumilasci Omar René
Publication year - 2003
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.0909-8836.2003.00087.x
Subject(s) - endocrinology , medicine , amylase , triiodothyronine , chemistry , methysergide , euthyroid , receptor , thyroid , cholinergic , hormone , serotonin , secretion , serotonergic , enzyme , biochemistry
The effects of 5‐hydroxytryptamine (5‐HT) upon amylase secretion by rat parotid glands were studied in three groups of animals: (a) intact control rats (euthyroid rats); (b) hypothyroid rats obtained by surgical thyroidectomy 2 wk before the experiments; and (c) hyperthyroid rats obtained by the administration of sodium l‐triiodothyronine for 2 wk before the experiments. Hyperthyroid rats showed significantly higher baseline amylase release than control rats. When the glands were stimulated with 5‐HT (30 µ m ), amylase release was significantly lower in the hypothyroid group and higher in the hyperthyroid rats than in control group. Addition of cholinergic, adrenergic or substance P antagonists did not modify 5‐HT‐stimulated amylase activity. The effects of 5‐HT were partly but significantly blocked by the addition of 10 µ m methysergide (HT 1/2/7 receptor blocker) in the three groups of rats. In contrast, 10 µ m ketanserine (HT 2A receptor blocker) partly blocked the response to 5‐HT only in the hyperthyroid animals. It was concluded that 5‐HT induces amylase secretion by rat parotid glands through specific serotoninergic receptors, and that thyroid status modulates the 5‐HT effect.