Expression of neuropeptides

A method of expressing a neuropeptide in a neuron of a subject, the method comprising:

• administering a first nucleic acid to the neuron in the subject, the first nucleic acid encoding the neuropeptide, wherein a first promoter is operably linked to the first nucleic acid, whereby the neuropeptide is expressed in the neuron;
• administering a second nucleic acid to the neuron in the subject, the second nucleic acid encoding a conditional receptor configured to increase activity of the neuron upon application of an agonist or stimulus, wherein the first promoter or a second promoter is operably linked to the second nucleic acid, whereby the conditional receptor is expressed in the neuron;
• and
• applying the agonist or stimulus to the neuron of the subject, causing the conditional receptor to increase activity of the neuron that expresses the neuropeptide.