Introduction

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            Bipolar disorder is a mental disorder that affects 5.7 million people in the USA (1). The disorder presents itself typically at 25 years old and affects all sexes and racial groups equally, but has been found to have a genetic component involved with its pathology. It was found that two thirds of people with the disorder had a close relative with either bipolar disorder or major depression. The disease is characterized by intense feelings of grandeur called a manic phase, followed by feelings of deep depression and hopelessness. The disorder is classified into four types; Bipolar 1, Bipolar 2, Cyclothymic Disorder, and Other. Each type varies in the length and intensity of the manic phase, bipolar type 1 is the most intense and becomes less with each type listed above. Symptoms include manic episodes that give feelings of euphoria and can lead to a number of secondary complications. On the opposite side of the bipolar spectrum is depression, after a manic episode, which normally lasts upwards of a week, a person with bipolar, will fall into a depression, which gives the feelings of hopelessness, and has a high risk of suicide associated with it. One in five people with bipolar disorder will commit suicide and an average decrease of 9.2 years is associated with the disorder (1).

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            Cell signaling pathways such as protein kinase C (PKC), PKA, mitogen-activated protein (MAP) kinase, glycogen synthase kinase 3-β (GSK3-β) and intracellular calcium regulate the dysfunction of bipolar disorder, and are involved in synaptic plasticity, the idea that synapses can change and create new connections when new information is presented to them. It has been shown that the glutamatergic system specifically the AMPA glutamate receptor also plays a major role in managing neural plasticity and can be used to treat and understand the major mood swings associated with bipolar. Two major treatments that down regulate the AMPA receptor GluR1 subunit are lithium and valproate this leads to a decrease in mood swings. It was found that lithium has a 70-85% success rate for the treatment of mania (1). In mice, imipramine was used to induce a manic episode showing an increase in GluR1 proving that this pathway could have major impacts on future research breakthroughs.