Some pharmacological properties of the alpha-toxin of staphylococcus pyogenes

Neurons, Receptors, and Channels

Here, I recount some adventures that I and my colleagues have had over some 60 years since 1957 studying the effects of drugs and neurotransmitters on neuronal excitability and ion channel function, largely, but not exclusively, using sympathetic neurons as test objects. Studies include effects of centrally active drugs on sympathetic transmission; neuronal action and neuroglial uptake of GABA in the ganglia and brain; the action of muscarinic agonists on sympathetic neurons; the action of bradykinin on neuroblastoma-derived cells; and the identification of M-current as a target for muscarinic action, including experiments to determine its distribution, molecular composition, neurotransmitter sensitivity, and intracellular regulation by phospholipids and their hydrolysis products. Techniques used include electrophysiological recording (extracellular, intracellular microelectrode, whole-cell, and single-channel patch-clamp), autoradiography, messenger RNA and complementary DNA expression, antibody injection, antisense knockdown, and membrane-targeted lipidated peptides. I finish with some recollections about my scientific career, funding, and changes in laboratory life and pharmacology research over the past 60 years.

On the mechanism of action of Colisan

Purified Colisan produces instantaneous lysis of paramecia and amoebae, and blebbing of paramecia, rat mast cells and ascites tumour cells. Colisan liberates histamine from mast cells. It also suppresses competitively the bradykinin-provoked contraction of the guinea-pig ileum. Most of these effects are not shared by staphylococcus-haemolysin. The results suggest a rapid change of the permeability of the cell membrane as the mechanism of all the diversified biological actions of Colisan.

A comparative study of staphylococcus haemolysins and Colisan

Staphylococcus beta-haemolysin exhibits the same broad spectrum of antagonistic activity against smooth muscle stimulants as described recently for Colisan. The antispasmodic effect develops slowly and can be removed only by repeated washing. The pattern of haemolytic activities of Colisan is characteristically different from that of beta-haemolysin, but resembles closely alpha-toxin. Both staphylococcus toxins can destroy paramecium and entamoeba, but the ratio of the titres at which they kill paramecium and entamoeba respectively (P:A value) is different. The P:A value of beta-haemolysin is similar to that of Colisan.