Cause of idiopathic sudden sensorineural hearing loss: The stress response theory

Table 2 Receptors of catecholamine in the cochlea

Location	Adrenergic receptor					Cholinergic receptor
	α1	α2	β1	β2	1β	M1	M2	M3	M5
IHC	○		○			○		○	○
OHC	○		○			○		○
Deiters’ cells			○	○		○	○	○	○
Hensen’s cells			○	○
Outer sulcus			○
Stria vascularis2				○
Strial marginal cell			○						○
Capillaries in the stria vascularis								○
Spiral ligament2			○	○		○	○	○	○
Rissener’s membrane					○
Spiral ganglion	○		○	○		○		○	○
Nerve fibers approaching HCs	○		○	○
Efferent fibers of the intraganglionic spiral bundle							○		○
Spiral modiolar artery	○	○
Endolymphatic sac				○

¹The specific receptor subtype, β1 or β2, was not determined;

²Note that the receptors were detected in tissues apart from blood vessels. IHC: Inner hair cell; OHC: Outer hair cell.