Multiple binding sites for inhibitory choline esters in spontaneous decarbamoylation of dimethylcarbamoyl-acetylcholinesterase (AChE) were suggested from a wide range of IC50 values, in contrast with a limited range of AC50 values (concentration giving 50% of maximal activation) at a peripheral activatory site. Association of choline esters containing a long acyl chain (C7-C12) with the hydroph...

ANY simple test, by means of which we can detect small amounts of free choline and distinguish between it and its water-soluble esters in tissue extracts, is of interest. It has been known for a long time that periodide solutions are very delicate precipitants for choline. In 1897 Florence used the periodide reagent in testing for semen. In 1901 Bocarius showed that the test was due to the pres...

The present report describes the effect of piipil size on the accommodation-convergence relationship. Measurements of accommodation and associated changes in convergence were made with a Fincham coincidence optometer and modified hagioscope. Responses were obtained over a wide range of stimulus levels with the observer viewing the target through a graded series of artificial pupils. Increasing ...

One characteristic of the most common types of glaucoma is increased intraocular pressure (IOP), which has a damaging effect on optic nerve axons, leading to progressive loss of retinal ganglion cells. Therefore, ocular hypotensive drugs are the mainstay of pharmacological therapy for glaucoma. This review article, which is the first part of a two-part series, is dedicated to autonomic drugs wh...

Vasodilating agents were tested on smooth-muscle strips of small arterial blood vessels of dog and rabbit skin and mesentery, and two patterns of reaction were demonstrated. The type 1 vasodilating agents, for example nicotinate, caused relaxation of contracted strips or blocked their contraction. The type 2 vasodilating compounds, histamine, choline esters, and bradykinin, either caused contra...

Despite significant advances in chemical ecology, the biodistribution, temporal changes and ecological function of most marine secondary metabolites remain unknown. One such example is the association between choline esters and Tyrian purple precursors in muricid molluscs. Mass spectrometry imaging (MSI) on nano-structured surfaces has emerged as a sophisticated platform for spatial analysis of...

Vasodilating agents were tested on smooth-muscle strips of small arterial blood vessels of dog and rabbit skin and mesentery, and two patterns of reaction were demonstrated. The type 1 vasodilating agents, for example nicotinate, caused relaxation of contracted strips or blocked their contraction. The type 2 vasodilating compounds, histamine, choline esters, and bradykinin, either caused contra...

The choline esters potentiated the choline-catalysed decarbamoylation of dimethylcarbamoyl-acetylcholinesterase in proportion to the length of acyl group, although esters containing an acyl chain longer than the hexanoyl group exhibited a corresponding decrease in the potentiation. In structural requirement analysis it was found that both the quaternary ammonium moiety and the ester bond were i...

The present investigation was undertaken to determine the relation between the structure of various substrates and the action of serum choline esterase upon them. The comparison of activities with different esters should take into account two factors : the hydrolytic velocities compared should be linear functions of time, and these velocities should be independent of substrate concentration. Th...

Specific acetylcholinesterases (ACHE) are found in neural and muscle tissues of mammals and birds and in the red blood cells of many mammals. They differ in many respects from the non-specific cholinesterases (BChE) in plasma and elsewhere in the body (Augustinsson 1963). One major distinction (amongst others) is that AChE enzymes hydrolyze acetylcholine more rapidly than other choline esters ;...