Brain dopamine receptor stimulation and the relief of Parkinsonism: relationship between bromocriptine and levodopa.

The relationship between dopamine receptor stimulation by bromocriptine or levodopa and the relief of parkinsonism was studied in 24 patients with Parkinson disease. Bromocriptine, 30 mg daily for 20 weeks, elicited an improvement in the parkinsonian clinical features, but this was less than the subsequent improvement with levodopa and benserazide, 800 mg and 200 mg daily, respectively. There was a negative correlation between the pretreatment severity of the disease or changes in cerebrospinal fluid homovanillic acid (HVA) and improvement in parkinsonian disability during bromocriptine treatment. Futhermore, it was found that clinical improvement and HVA responses in the cerebrospinal fluid after dopamine receptor stimulation by bromocriptine may predict the clinical response to levodopa.