Effect of Reserpine Pretreatment on Avian Erythrocyte Carbonic Anhydrase Activation by Isoproterenol

Abstract

We studied the action of β-adrenergic agonists on Japanese quail erythrocyte carbonic anhydrase (CA) in vitro. Earlier we had reported that epinephrine increased CA activity by 14%; the present study focused on an attempt to increase the size of this response. Washed erythrocytes from reserpine-treated (1 mg/kg daily i.m. for 3 days) and control birds were incubated for 40 min in the presence of isoproterenol 10^–6 mol/l. The activity of CA expressed as Wilbur-Anderson units/mg hemoglobin was increased by as much as 42% in reserpine-treated birds over the control depending on the conditions. Addition of 10^–5 mol/l of the β-adrenergic antagonist propranolol inhibited the isoproterenol-induced effect in nonreserpinized birds. We conclude that pretreatment with reserpine, which was accompanied by a fall in plasma catecholamine levels, particularly epinephrine levels, enhanced the activation of CA by isoproterenol.

Carbonic Anhydrase Activation and the Drug Design

“…In the last decades this research area was relaunched in the light of new discoveries: 1-The report of CA II activation by phosphorylation in the presence of protein kinases and cAMP [33]. 2-Some anionic activators of CA III have also been reported [7], the effect being explained as due to the proton shuttling capacities of such molecules.…”

Carbonic Anhydrase Activators: X-ray Crystallographic and Spectroscopic Investigations for the Interaction of Isozymes I and II with Histamine,

“…In contrast to inhibitors, activators of CAs were less studied, probably because CA is one of the most efficient enzymes known (Roughton, 1943;Clark & Perrin, 1951). Still, CA II activation by phosphorylation in the presence of protein kinases and cAMP has been reported (Narumi & Miyamoto, 1974) and recently reconfirmed (Igbo et al, 1994). Some anionic activators of CA III have also been reported (Shelton & Chegwidden, 1988;Paranawithana et al, 1990;Rowlett et al, 1991), the effect being explained as due to the proton shuttling capacities of such molecules.…”