Table 1.

Research results to date regarding the effects of chewing on stress-induced brain and systemic responses.

Brain region	Sub-nucleus	Marker	Stress	Stress with chewing	Refs.
Hippocampus		BDNF mRNA	↓	↑	[17]
		NT-3 mRNA & protein	↑	↓	[17]
	CA1	MR	↑	↓	[51]
	CA1	GR	↓ or ±	↑	[30], [51]
	CA1	NMDA receptor	↓	↑	[42]
	CA1	H1 receptor	↓	↑	[42]
	DG	Cell birth	↓	↑	[83]
Hypothalamus		Free radical	↑	↓	[11]
	PVN	c-fos	↑	↓	[25]
	PVN	CRF protein	↑	↓	[20]
	PVN	nNOS mRNA & protein	↑	↓	[88]
	PVN	pERK1/2	↑	↓	[22]
Periaqueductal gray	dl	pERK1/2	↑	↓	[60]
	vl	pERK1/2	↑	↓	[60]
Insular cortex	Ant	pERK1/2	↑	↓	[72]
	Post	pERK1/2	↑	↓	[72]
Amygdala	CeA	GABA	±	±	[34]
	BLA	GABA	↑	↑↑	[34]

Target area	Representation or behavior	Stress	Stress with chewing	Refs.
Hippocampus	Goal in time on Morris water maze	↓	↑	[30]
	LTP	↓	↑	[38]
	LTD	↑	↓	[84]
Blood level	ACTH	↑	↓	[17]
	Corticosterone	↑	↓	[17]
	IL-1β	↑	↓	[85]
	IL-6	↑	↓	[85]
	Leptin	↑	↓	[85]
	TSH	↓	↑	[85]
	Noradrenaline	↑	↓	[3]
Hypothalamus	PO2	↓	±	[86]
	Blood-flow	±	↑	[86]
	NO	↑	↓	[87]
Amygdala	PO2	↓	↑	[86]
	Blood-flow	±	↑	[86]
Cardiovascular system	Arrhythmias	↑	↓	[3]
	Blood pressure	↑	↓	[85]
Body-wide	Sympathetic activity	↑	↓	[3]
	Core temperature	↑	↓	[85]

Abbreviations: BDNF: brain-derived neurotrophic factor; NT-3: neurotrophin-3; MR: mineralocorticoid receptor; GR: glucocorticoid receptor; NMDA: N-methyl-d-aspartate receptor; H1 receptor: histamine receptor 1; CRF: corticotropin-releasing factor; nNOS: neuronal nitric oxide synthase; pERK1/2: phosphorylated extracellular signal-regulated kinase; GABA: gamma-aminobutyric acid; LTP: long-term potentiation; LTD: long-term depression; ACTH: adrenocorticotropic hormone; IL-1β: interleukin-1β; IL-6: interleukin-6; TSH: thyroid-stimulating hormone; PO₂: partial pressure of oxygen; NO: nitric oxide.