Local Anesthetic Activity of β-Adrenergic Blocking Drugs in the Crayfish Giant Axon, with Reference to Calcium Ion

Open Access
Publisher Website
Google Scholar
Abstract
The secretory responses to 7 dopamine, amino acid conjugated derivatives were compared with those to dopamine, using blood-perfused canine pancreas preparations. Each of these dopamine derivatives produced a dose-dependent increase in the secretion of pancreatic juice. The rank order of the secretory responses and relative potency (dopamine = 1) were as follows: N-Ileu-dopamine (0.4) > N-Ala-Glu-dopamine (0.2) > N-.gamma.-Glu-dopamine (0.1) = N-Gly-Pro-dopamine (0.1) > N-Gly-Gly-dopamine (0.01) > N-Gly-Gly-Leu-dopamine (0.005) = N-Gly-Gly-Pro-dopamine (0.005). The duration of action of doses of the derivatives, which produced appoximately equal secretory responses, was .apprx. 1.2-2.7 times longer than that of dopamine. Dopamine and N-Ileu-dopamine, which has the most potent secretagog property among 7 dopamine derivatives, produced a secretin-like secretion of the pancreatic juice; this contained a high concentration of bicarbonate, but had little effect on protein output with lower amylase activity.