Here is a list of acronyms and their definitions. * 5-HT : 5-hydroxytryptamine * Ach : Acetylcholine * AChE : acetylcholinesterase * ACTH : adrenocorticotropic hormone * AMPA : α-amino-3-hydroxy-5-methylisoxazole-4- propionic acid receptor * BDNF : Brain derived neurotrophic factor * cAMP : Cyclic AMP * cGMP : cylic guanosine 3'-5' monophosphate * CREB : cAMP response element-binding * DA : Dopamine * ERa : Estrogen Receptor a * GABA : Gamma-aminobutyric acid * GTP : guanosine triphosphate * IP3 : inositol trisphosphate * LTD : Long-term Depression * LTP : Long-term Potentiation * MAPK : Mitogen-Activated Protein Kinase * NFkB : nuclear factor-kappa B * NGF : Nerve growth factor * NMDA : N-methyl-D-aspartic acid