Amphetamines, like all phenethylamines typically, are not direct-acting sympathomimetic, but indirect-acting; amphetamines elicit their effects through blockage and reversal of NET and DAT, the norepinephrine and dopamine transporter proteins. They are, however, TAAR1 agonists, which is currently thought to be partially responsible for regulating downstream effects on dopamine neurotransmission.
LSD is best described as a lysergamide.
Why does smoking have an immediate intensification effect when combined with lysergamides? Is it because of the combination of partial antagonism and down regulation blocking of certain receptors?