Neurotransmitter Molecules Neurotransmitters Neurotransmitters can be broadly split into two groups – the ‘classical’, small molecule neurotransmitters and the relatively larger neuropeptide neurotransmitters. Within the category of small molecule neurotransmitters, the biogenic amines (dopamine, noradrenaline, serotonin and histamine) are often referred to as a discrete group because of their similarity in terms of their chemical properties.
Central neuropeptides, including corticotropin releasing factor and perhaps substance P as well, initiate a systemic stress mobilization response by activating the sympathetic nervous system, hypothalamic pituitary axis, and the renin angiotensin system,
Even the lowest dose of modafinil, an ampakine, improved the wakefulness and cognitive performance of sleep-deprived people; they work in part by boosting glutamate, a key neurotransmitter that facilitates learning & learn and encodes memory.