Fig. 12.

Spinal cord neurons show calcium rise in response to hypocretin. A, Hypocretin-2 (H, 1 μm) was added by bath perfusion. In the presence of hypocretin, cytoplasmic calcium increased as measured with fura-2 imaging. Horizontal lines mark the presence of the peptide. B, A neuron responds both to hypocretin-1 (H-1) and hypocretin-2 (H-2) but not to the 17-amino acid inactive C-terminal fragment (17) of preprohypocretin. C, D, In two neurons recorded simultaneously, the response to hypocretin-2 (H, 1 μm) and oxytocin (Oxy, 1 μm) was compared. InC, the neuron responds to hypocretin but shows little response to oxytocin. The neuron in D responds to both oxytocin and hypocretin.