Adrenergic receptors in Parkinson's disease

Alpha 1, alpha 2, beta 1 and beta 2 adrenergic receptors were measured in the pre-frontal cortex of parkinsonian patients post-mortem. The number of beta 2 receptors was the same in control and parkinsonian subjects. alpha 1 and beta 1 receptors increased in number, particularly in demented parkinsonian patients, while alpha 2 receptors decreased. The affinity constants were unchanged. The modifications seem to be related to lesion of the noradrenergic pathway from the locus coeruleus to the cortex. The relationship between this lesion and the symptoms of dementia and depression in parkinsonian patients is discussed.