Table 3.

The effects of chronic stress on dendritic spines in the amygdala.

#	Stress	Paradigms	Animals	Amygdala	Function	Proteins	References
1	CRS	6 h/day for 21 days	Wt C57/BL/6 mice	↓ spine density in WT medium spiny stellate neurons MeA, ↑ spine density in Wt BLA	↔ spinogenesis in BLA OF tPA−/− mice	tPA−/− mice reverse stress-induced reduction of spine density in MeA	[114]
2	CRS	6 h/day for 28 days	Male young, Wistar rats	↔ spine density in MePD			[115]
3	CRS	1 h/day for 10 days	Male ICR mice	↓ eIPSC, ↑ LTD GABAergic synapse in BLA	MAGL inhibition prevents depression-like behavior	2-AG ↑, MAGL ↓	[116, 117]
4	CRS	2 h/d for 10 days	Male Wt mice	↑ BLA dendritic branching ↑ spine density in BLA apical and basal dendrites ↑ spine length ↑ anxiety behavior	Fmr1 KO mice fail to show anxiety	In Fmr1 KO mice ↔ spine length in BLA ↓ spine density in BLA	[118]
5	CRS	1 h/day for 21 days	Male GIN mice	↔ spine density, ↓ dendritic arborization in interneurons in LA and BLA		GAD67, synaptophysin and PSA-NCAM ↓	[119]
6	CRS	2 h/day for 10 days	Male ICR mice	↑ dendritic length and branch points in BLA, which are blocked by tianeptine	Depression-like behaviors are blocked by tianeptine	Tianeptine is an antidepressant	[120]
7	CRS	1 h/day for 14 days	Male SD rats	Impaired LTP in the NAc 30 days after stress termination	CB1/2R agonist prevents the stress-impaired LTP	↓ GRs in amygdala and NAc	[121]
8	CRS	20 min/day 7 out of 9 days	Male SD rats	↑ dendritic length in BLA, ↑ spine density in LA and BA, but proximal increase in LA, nonproximal increases in BA	↑ frequency of sEPSC in vivo		[122, 123]
9	CRS	6 h/day for 21 days	C57/Bl6 mice	↑ dendritic arborization ↑ spine density in BLA ↑ anxiety-like behaviors	CRS-induced changes in structure and behaviors are abolished in FAAH KO mice		[124]
10	Acute restraint stress CRS	Single 1 h	Male young adult	↓ Spine density in the posterodorsal MePD			[115]
		Single 6 h 6 h/day for 28 days		↔ spine density in MePD
11	CIS CUMS	2 h/d for 10 days 10 days	Male Wistar rats	↑ dendritic arborization in BLA pyramidal and stellate neurons Dendritic atrophy in BLA bipolar neurons			[50]
12	CIS	2 h/d for 10 days	Male Wistar rats	↔ dendrites in CeA ↑ dendrites in BNST			[125]
13	CIS	2 h/d for 10 days	Male Wistar rats	↑ dendritic length in BLA			[126]
14	CIS	2 h/d for 10 days	Male Wistar rats	↑ spine density in the BLA			[127]
15	CIS	2 h/d for 21 days	Male Wistar rats	↑ dendritic arborization BLA, ↑ spine density ↑ synaptic connectivity	↑ anxiety-like behavior		[128]
16	CIS	2 h/day for 10 days	Male Wistar rats	↑ spine density in BLA LTP ↑ (thalamic-LA)	sIPSC frequency ↓		[129]
17	AIS	2 h	Male Wistar rats	↔ spine density or dendritic arborization 1 d later, ↑ spine density 10 d later in BLA			[127]
18	CUMS	8 weeks	Adult male SD rats	↑ synaptic length of the active zone in BLA ↑ PSD thickness in BLA	↑ synaptic proteins are correlated with depression-like behaviors	↓ PSD93, ↔ PSD95, and ↔ spinophilin ↔ synapsin ↔ synaptophysin	[52]
19	CUMS	14 days	Male Swiss albino mice	↑ spine density in BLA ↑ dendritic length in BLA	Associated with depression-like behaviors		[51]
20	Chronic CORT	20 days	C57BL/6 mice	↑ spine density in BLA, recovery to normal level with a washout period			[130]
21	CORT drinking water	50 μg/mL for 14 days	Adult male SD rats		↑ GluR1 and synaptophysin in the LA	↑ IEGs Arc/Arg3.1 and Egr-1 in the LA	[131]
22	Single prolonged stress	2 h restraint, 20 min forced swimming	Adult male SD rats	↑ dendritic arborization in BLA ↔ in CeA neurons		↑ NPY ↔ CaMKII and MR/GR expression in the BLA	[132]
23	Single elevated platform acute stress	30 min, single	Male SD rats	↑ total spine density ↑ mushroom spine density in BLA; ↓ number and the length of branches in BLA			[133]
24	Chronic social instability stress	1 h/day for 35 days	Adolescent 28-day-old SD rat	↓ spine density in BLA		↑ truncated TrkB, ↓ full-length TrkB and SNAP-25	[134]
			Adult, 56-day-old SD rat	↑ spine density in BLA		↑ full-length and truncated TrkB

CRS: chronic restraint stress. CUMS: chronic unpredictable mild stress. CIS: chronic immobilization stress. AIS: acute immobilization stress. BA: the basal nucleus of the amygdala. BLA: the basolateral amygdala. LA: the lateral nucleus of the amygdala. MePD: posterodorsal medial amygdala. eCB: endocannabinoid. 2-AG: eCB 2-arachidonoylglycerol. MAGL: monoacylglycerol lipase, an enzyme for degrading 2-AG. CORT: corticosterone. Tianeptine: an antidepressant. ↔: no change. ↓: decrease. ↑: increase.