Allosteric modulation of cholinergic system: Potential approach to treating cognitive deficits of schizophrenia

Table 1 Muscarinic receptors in post-mortem studies

Ref.	Receptor Type		Regions	Results
	Protein	mRNA
[114]	M1/M4		CPu	Lower binding
[115]	M2/M4		CPu	Lower binding
[116]		M1 M2	CPu	M1 no difference; M2 below sensitivity in both SCZ and HC
[117]	M1/M4		PFC	Lower binding
[76]	M1/M4	M1 M4	DLPFC; PCx	Lower binding and M1 mRNA levels in DLPFC; no difference in binding, lower M1 and M4 mRNA levels in PCx
[118]		M1	PMC	Lower levels
[119]	M1/M4		ACC	Lower binding
[120]	M2/M4		ACC	No difference
[121]	M1/M4 M2/M4		STG	Lower M1/M4 binding non-significant; lower M2/M4 binding
[77]	M2 M3	M2 M3	DLPFC; PCx	M2 and M3 binding and M3 mRNA no difference; M2 mRNA below sensitivity in both SCZ and HC
[122]	M1/M4	M1 M4	Hipp	Lower binding; lower M4 mRNA no difference in M1 mRNA levels
[123]	M1/M4 M3		PMC	Lower M1/M4 binding; no difference in M3 binding
[78]	M1		DLPFC	Lower binding in subset of SCZ subjects
[81]	M1 M3	M1 M3 M4	PMC	Lower M1 binding in subset of SCZ subjects; no difference in mRNA levels or M3 binding
[82]	M1		DLPFC; ACC; BrA	Lower binding in subset of SCZ subjects

“/” Indicates that the radioligand used in the study binds both receptor types listed. CPu: Caudate-putamen; SCZ: Subjects with schizophrenia; HC: Non-psychiatric healthy control; PFC: Prefrontal cortex; DLPFC: Dorsolateral prefrontal cortex; PCx: Parietal cortex; PMC: Premotor cortex; ACC: Anterior cingulate cortex; STG: Superior temporal gyrus; Hipp: Hippocampus; BrA: Broca’s area.