Wherefore Art Thou, Homeo(stasis)? Functional Diversity in Homeostatic Synaptic Plasticity

Table 1

Homeostatic synaptic adaptations to chronic inactivity. An overview of select references which have investigated the neuronal response to chronic inactivity via functional analyses of AMPA receptor-mediated excitatory synaptic transmission. References are arranged by cell type (column 1) and inactivity paradigm (column 2). Within each paradigm, studies are listed in ascending age order (column 3). ↑,↓ = significant change in mEPSC amplitude or frequency. — = no change in parameter. N/A = parameter was not reported. *mEPSC frequency was not directly measured.

Cell type	Inactivity paradigm	Days in vitro (DIV) or postnatal day (P)	Amp.	Freq.	Reference
In vitro (dissociated culture)
Spinal cord	CNQX + APV	DIV 10	↑	—	[23]
Cortex (Ctx)	CNQX + APV	DIV 21	↑	↑	[37]
Ctx	APV	DIV 7–9	—	—	[38]
Ctx	CNQX	DIV 7–9	↑	—	[38]
		DIV 14–17	↑	↑	[39]
Ctx	TTX	DIV 7–9	↑	—	[38]
		DIV 7–10	↑	—	[40]
		DIV <10	↑	—	[41]
		DIV 11–13	↑	—	[42]
		DIV 14	↑	—	[43]
		DIV >18	↑	↑	[41]
Hippocampus (Hpc)	TTX	DIV 7	↑	—	[44]
		DIV 10	↑	—	[41]
		DIV 14	↑	↑	[45]
		DIV 14	↑	↑	[44]
		DIV 14	↑	—	[35]
		DIV 14	↑	—	[46]
		DIV 14	↑	N/A	[47]
		DIV 18	↑	↑	[41]
		DIV 21-22	↑	—	[48]
		DIV 21	N/A	“↑” *	[29]
		DIV 27–40	↑	—	[49]
Hpc	TTX + APV	DIV 14	↑	—	[35]
		DIV 14-15	↑	—	[50], [46]
Hpc	TTX + CNQX	DIV 14	↑	—	[46]
Hpc	TTX + NBQX	DIV 27–40	↑	—	[49]
Hpc	NBQX	DIV 14–16	↑	↑	[36]
		DIV 17	↑	↑	[51]
		DIV 17	↑	↑	[24]
		DIV 21	N/A	“↑” *	[29]
		DIV 27–40	↑	↑	[49]
Hpc	CNQX	DIV 14	↑	—	[46]
		DIV 21	↑	↑	[46]
		DIV 21–38	↑	↑	[49]
Hpc	Kir2.1 expression	DIV 14-15	—	↑	[45]
		DIV 15–24	↑	N/A	[52]
In vitro (organotypic slice, all from P6-8 cultures)
Hpc	TTX	DIV 8 (CA3)	↑	↑	[53]
		DIV15 (CA3)	↑	↑	[53]
		DIV 21–25 (MF-CA3)	—	↑	[54]
		DIV 21–25 (CA3-CA3)	—	↓	[54]
		DIV 21–25 (CA3-CA1)	—	—	[54]
Hpc	TTX + APV	DIV 5–7 (CA1)	↑	—	[55]
		DIV 6–8 (CA1)	↑	—	[50]
Ex vivo (acute slice)
Hpc	TTX ex vivo incubation	P4 (CA3)	↑	↑	[53]
		P8 (CA3)	—	—	[53]
		P21–28 (CA1)	—	—	[35]
Hpc	TTX in vivo implantation	P15 (CA1)	↑	↑	[56]
		P30 (CA1)	—	↑	[56]
Hpc	TTX + APV ex vivo	P21–28 (CA1)	↑	—	[35]
Visual cortex	Intraocular TTX	P21	↑	—	[27]
	Monocular deprivation	P21	↓	↓	[27]
	Binocular deprivation	P23	↑	—	[57, 58]