Table 2.

Prenatal Distribution (E15–E21) of the Small-Conductance Calcium-Activated Potassium Channel Subunit SK2¹

Brain region	E15	E17	E19	E21
Olfactory system
Olfactory bulb
Glomerular layer	np	np	−	−
Mitral cell layer	np	np	+	+
Internal granular layer	np	np	np	+
Accessory olfactory bulb	np	−	−	−
Anterior olfactory nucleus	np	•	++	++
Olfactory tubercle	np	np	+	++
Cerebral cortex
Piriform cortex	•	•	++	++
Primordial plexiform layer	+++	np	np	np
Cortical neuroepithelium	++	+	++	+
Molecular layer	np	−	−	−
Cortical plate	np	+++	+++	+++
Intermediate zone	np	+	++	+++
Subventricular zone	np	+	+	−
Hippocampal formation
Subicular neuroepithelium	++	++	np	np
Subiculum (or diff. field)	np	+++	+++	+++
Hippocampal neuroepithelium	++	++	np	np
Hippocampus (or diff. field)	+++	+++	np	np
CA1	np	np	+++	+++
CA3	np	np	++	++
Dentate gyrus granule cells	np	np	−	−
Basal ganglia
Striatum (or diff. field)	+++	++	−	−
Thalamus
Anterior thalamus (or diff. field)	−	++	++	++
Posterior thalamus (or diff. field)	−	++	++	++
Intermediate thalamus (or diff. field)	−	•	++	++
Trigeminal ganglion	++	+++	+++	+++
Inferior glossopharyngeal ganglion	•	•	+++	+++
Pons (or diff. field)	+++	++	+++	•
Cerebellum
Cerebellar neuroepithelium	−	−	np	np
Cerebellum (or diff. field)	+++	+++	np	np
Deep nuclei	np	np	−	−
Purkinje cell layer	np	np	+++	+++
External germinal layer	np	•	−	−
Granule cell layer	np	np	−	−
Spinal cord	+++	+++	•	•
Dorsal root ganglia	++	+++	•	•
Intestine	+++	++	•	•

¹+++, strong; ++, moderate; +, weak; −, signals very low or below the threshold limit of detection; np, not present; •, not clearly identifiable; Diff. field, differentiating field.