Thermal stimulation of taste

The first electrophysiological recordings from animal and human taste nerves gave clear evidence of thermal sensitivity, and studies have shown that as many as half of the neurons in mammalian taste pathways respond to temperature. Because temperature has never been shown to induce sensations of taste, it has been assumed that thermal stimulation in the gustatory system is somehow nulled. Here we show that heating or cooling small areas of the tongue can in fact cause sensations of taste: warming the anterior edge of the tongue (chorda tympani nerve) from a cold temperature can evoke sweetness, whereas cooling can evoke sourness and/or saltiness. Thermal taste also occurs on the rear of the tongue (glossopharyngeal nerve), but the relationship between temperature and taste is different there than on the front of the tongue. These observations indicate the human gustatory system contains several different types of thermally sensitive neurons that normally contribute to the sensory code for taste.     

Denervation atrophy: Enzyme changes in the control muscle

Riassunto Sono state studiate le due forme principali (M e H) della deidrogenasa lattica nel muscolo soleo della gamba enervata e di quella del lato opposto, nel coniglio. Animali non operati servirono come controlli. La forma H, che predomina nel soleo normale, sperimentò una notevole diminuzione dopo enervazione. La forma M non sperimentò modificazione nel soleo enervato, ma aumentò in quello del lato opposto.     

Cultured epithelial cells of cornea, conjunctiva and skin: absence of marked intrinsic divergence of their differentiated states.

Keratinocytes of three different epithelia grown in cell culture express a large number of differentiation markers with either no differences or relatively small differences, depending on the species. Much of the distinctive phenotype of these epithelia in vivo must be due to external modulation and relatively little, at least in the case of the human, to permanent intrinsic divergence during development.