Methods of facilitating neural cell survival using non-peptide and peptide BDNF neurotrophin mimetics

1. A method of treating a disorder in a subject in need thereof, comprising administering to the subject an effective amount of a compound that is an agonist or partial agonist of a TrkB receptor, thereby treating the disorder,

wherein the compound is a small molecule mimetic of a brain-derived neurotrophic factor (BDNF) β-turn loop, wherein the β-turn loop is loop 2, and the small molecule mimetic has a structure of Formula (II):

or a pharmaceutically acceptable salt thereof;

wherein:

L 2 is:

L 1 , L 3 , and L 4 are independently C 1 -C 5 alkylene;

Y 1 , Y 2 , and Y 3 are each carbonyl or sulfonyl;

X 3 , X 4 , and X 5 are each N;

Z 1 , Z 2 , and Z 3 are independently selected from the group consisting of H and C 1 -C 8 alkyl; and

D 2 , D 3 , and D 4 are hydroxyl;

and

wherein the disorder is selected from the group consisting of Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, Rett syndrome, Parkinson's disease, spinal cord injury, stroke, ischemia, brain injury, motor neuron disease, multiple sclerosis, HIV dementia, peripheral nerve injury, hearing loss, and obesity.

2. The method of claim 1 , wherein the subject is a human subject.

3. The method of claim 1 , wherein the compound is

or a pharmaceutically acceptable salt thereof.

4. The method of claim 1 , wherein the disorder is Alzheimer's disease, Huntington's disease, stroke, Rett syndrome, multiple sclerosis, or Parkinson's disease.

5. The method of claim 3 , wherein the disorder is Alzheimer's disease, Huntington's disease, stroke, Rett syndrome, multiple sclerosis, or Parkinson's disease.