Thyroxin and calcitonin secretion into thyroid venous blood is regulated by pharyngeal mechanical stimulation in anesthetized rats

Abstract

The effects of the pharyngeal non-noxious mechanical stimulation on the secretion of immunoreactive thyroxin (iT4), immunoreactive calcitonin (iCT), and immunoreactive parathyroid hormone (iPTH) into thyroid venous blood were examined in anesthetized rats. Secretion rates of iT4, iCT, and iPTH were calculated from their concentration in thyroid venous plasma and the plasma flow rate. A mechanical stimulation was delivered to the pharynx by a rubber balloon placed on the tongue that was intermittently pushed into the pharyngeal cavity. Pharyngeal stimulation increased iT4 and iCT secretion, but iPTH secretion was unchanged. The secretion responses were abolished by transecting the superior laryngeal nerves (SLNs) bilaterally. The activities of the thyroid parasympathetic efferent nerves and the afferent nerves in the SLN increased significantly during pharyngeal stimulation. These results indicate that pharyngeal mechanical stimulation promotes thyroxin and calcitonin secretion from the thyroid gland by a reflex increase in SLN parasympathetic efferent activity, triggered by excitation of SLN mechanoreceptive afferents.

Fetal blockade of nicotinic acetylcholine transmission causes autism-like impairment of biological motion preference in the neonatal chick

“…Among the possible candidates, the following regions need specific attention: (i) cholinergic neurons in the striatum and the basal forebrain projecting to wide areas in pallium (or cortex in mammals) ( Ahmed et al. 2019 ), (ii) cholinergic neurons in nucleus isthmi parvocellularis (or pedunculo-pontine tegmental nucleus) projecting to optic tectum (superior colliculus) ( Knudsen 2011 ), and (iii) preganglionic cholinergic terminals of parasympathetic nerve acting on thyroid gland ( Iimura et al. 2019 ).…”

Fetal imidacloprid causes ASD-like impairment of biological motion perception in neonatal chicks

“…However, as nAChR is widespread in the brain and body103–105, several brain regions/organs must be considered. Among the possible candidates, the following regions need specific attention: (1) cholinergic neurons in the striatum and the basal forebrain projecting to wide areas in pallium (or cortex in mammals)106, (2) cholinergic neurons in nucleus isthmi parvocellularis (or pedunculo- pontine tegmental nucleus) projecting to optic tectum (superior colliculus)107–109, and (3) pre-ganglionic cholinergic terminals of parasympathetic nerve acting on thyroid gland110. If (1) is the case, involvement of telencephalon in the BM predisposition should be considered as delayed GABA switch may be an underlying factor in the brain areas along with IMM, arco and tectum.…”

Chronic Electrical Stimulation of the Superior Laryngeal Nerve in the Rat: A Potential Therapeutic Approach for Postmenopausal Osteoporosis

“…In rodents, endogenous CT has also been shown to play a role in regulating postprandial hypercalcemia [ 17 ]. A recent study revealed that pharyngeal mechanical stimulation, like during eating, increases iCT secretion by a neurogenic reflex through the SLN [ 18 ]. Therefore, stimulation of the SLN during daytime, when rats do not eat, was expected to be effective in inhibiting bone loss.…”

“…However, there were no statistically significant findings between OVX SLN stimulation and OVX sham stimulation groups in any of the results on bone histomorphometry (Table 2). through the SLN [18]. Therefore, stimulation of the SLN during daytime, when rats do not eat, was expected to be effective in inhibiting bone loss.…”