Normal function requires intact neural, vascular and muscle processes with interactions of multiple neurotransmitters and endocrine system modulating influences.
A number of agents play a role including neurotransmitters, bioactive substances, and sex hormones and include: dopamine, norepinephrine, serotonin, acetylcholine, nitric oxide, melanocortin stimulating hormone, vasoactive intestinal peptide, prostaglandins, estrogen, progesterone, testosterone, prolactin, and oxytocin.
There are three functional domains of sexual response and they include desire, arousal and orgasm.
Sexual desire includes spontaneous sex drive and cognitive motivation.