Neurochemistry in the context of the biological approach refers to the chemical processes occurring in the nervous system. For example, the actions of neurotransmitters within the brain.Serotonin. You probably already know that serotonin plays a role in sleep and in depression, but this inhibitory chemical also plays a major role in many of your body's essential functions, including appetite, arousal, and moodGlutamate is excitatory, meaning that the release of glutamate by one cell usually causes adjacent cells to fire an action potential. ... GABA is an example of an inhibitory neurotransmitter. Monoamine neurotransmitters: Dopamine is a monoamine neurotransmitter.Hormones: Hormones are found in both plants and animals. Neurotransmitters: Neurotransmitters are found only in animals.Hormones: Hormones are produced in endocrine glands and are secreted into the blood stream. Neurotransmitters: Neurotransmitters are released by presynaptic nerve terminal into the synapse.