Another plant, Pausinystalla yohimbe (Yohimbine), an indigenous
of West African countries has been used as a pharmacological
agent in the treatment of ED and the drug is an alpha-2-
adrenergic receptor antagonist (MacKay, 2004). Yohimbine
improves sexual function by displacing epinephrine from
alpha-2 adrenergic receptors in the pelvic areas and it increases
the proneness to arousal through supplying epinephrine from the
alpha-2 receptors to the central nervous system (brain) where it
is active as a neurotransmitter (Riley, 1994).