Intraluminal volume homeostasis

Figures & data

Figure 1 Mammary epithelial serotonin system and its mechanism of action. Diagramatic representation of mammary epithelial serotonin system. Mammary epithelial cells synthesize serotonin and secrete it into their surroundings. This serotonin acts in an autocrine-paracrine manner through its receptors. Among these, 5-HT₇ receptor has been localized to the baso-lateral side of the mammary epithelial cells. 5-HT through the 5-HT₇ receptor generates two signals; a cAMP-PKA signal and a cAMP-p38^MAPK signal. Serotonin reuptake transporter (SERT) is present on the apical membrane of the mammary epithelial cells and is involved in recycling and metabolism of mammary serotonin.

Table 1 Serotonin receptor expression in ductal organs

Organ/Tissue	Receptor	Function	References
Mammary Gland
Epithelial cells (immortal and primary)	5HT7	Tight junction regulation	53
Isolated epithelial cells	5HT1D, 5HT2B, 5HT3A	Unknown	8, 14
Bovine epithelium	5HT1B, 5HT2A, 5HT2B, 5HT4, 5HT7	Suppression milk gene expression	9
Salivary Glands
Submandibular gland homogenate	5-HT1A, 5HT4B, 5HT7A	Inhibit fluid secretion	10
Liver
Cholangiocytes	5HT1A, 5-HT1B	Inhibit Proliferation and inhibit bile secretion	21
Pancreas
Isolated interlobular ducts	5HT3	Inhibit HCO3^- secretion	30
Lungs
Neuroepithelial bodies	5HT3	Oxygen sensing	33
Neuroepithelial cells	?	Inhibit secretion and induce fluid resorbtion	38, 39
Thyroid
Follicular cells	5-HT1 and 5-HT2	Biphasic action on growth and inhibition of hormone secretion	40
Prostate
Human prostate homogenate	5HT1A, 5HT1B, 5HT1D	Growth promoting in cancers	42

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