However, cAMP can also stimulate cell proliferation by stimulating ERKs. They primarily stimulate the pancreas and gall bladder, but also suppress gastric secretion and motility. Other factors must stimulate the BTC to increase transcription levels. Tumors can produce exosomes that stimulate inflammation via MDSCs. Laughter may also stimulate endorphin production and elevate one's pain threshold. Neurotrophins are chemicals that help to stimulate and control neurogenesis. Neutrophils can secrete products that stimulate monocytes and macrophages. This activates 5-HT3 receptors in the chemoreceptor trigger zone that stimulate vomiting. Although the body requires oxygen for metabolism, low oxygen levels normally do not stimulate breathing. When used at anesthetic doses, it will usually stimulate rather than depress the circulatory system. Peptones stimulate duodenal G cells to secrete gastrin. There are many ways to stimulate the clitoris. This metaphor can be powerful enough to stimulate people to action. High doses of alcohol do not stimulate secretion of acid. Antigens that stimulate B cells directly.