if such theoretical considerations apply to opiate receptors ( as drug receptors ) and to catecholamine receptors ( as physiological receptors ) , then the theory predicts that acute morphine administration increases the sensitivity of dopamine receptors , that sympathetic stimulation decreases pain sensitivity , that opioid tolerance provokes increased catecholamine activity , that alpha-receptor stimulants attenuate and alpha-receptor antagonists exacerbate morphine abstinence , and that catecholaminergic inhibition results in increased morphine toxicity .
C0054861
catecholamine receptors
C0034798
dopamine