The Application of a Technique for Counting Synaptosomes in an Investigation of the Effect of Hypothyroidism on the Number of Synapses in Certain Regions of the Rat Brain

Abstract

A technique for enumerating synaptosomes first developed by Clementi Whittaker and Sheridan (1966) was investigated. Various modifications were examined but none proved more effective than the original method. The technique was used to determine the number of synapses in the developing rat brain and in the brains of rats subjected to thyroidectomy. It was shown that the technique, when used with care and attention to detail, could be successfully applied to this type of investigation. Some results obtained parallel those achieved by other workers using different techniques, whilst other results provide new information on the effect of thyroidectomy on synaptogenesis. The pros and cons of the Clementi technique, and of other possible procedures for the enumeration of cortical synapses, was critically discussed. The possible significance of the effect of thyroidectomy on the mitochondria, structure and function of synapses was considered in relation to the mental deficiency associated with cretinism.