The gustatory sense in foetal sheep during the last third of gestation

Abstract

SUMMARY1. Histological studies revealed that presumptive taste buds are present in the foetal sheep tongue at 50 days. By 100 days the taste buds appear morphologically mature.2. To determine if foetal taste buds are functional, electrophysiological recordings were made of activity in the chorda tympani nerve of sheep foetuses. Single and multi-fibre preparations were studied in foetuses aged 100 days to term.3. Responses were recorded to lingual stimulation with salts, acids, glycerol, glycine, sodium saccharin, quinine HCl and amniotic fluid. Responses of the foetal chorda tympani to lingual stimulation with a series of monochloride salts and with increasing concentrations of one salt were similar to responses recorded in lambs and adults.4. The peripheral gustatory system of the foetal sheep is functional for at least the last third of gestation. Foetal taste experiences may influence the formation of adult taste preferences or may aid the foetus in monitoring its environment.

Maturation of neuron types in nucleus of solitary tract associated with functional convergence during development of taste circuits

“…Fetuses were delivered onto a water-circulating heating pad on a table next to the ewe and were covered with cotton pads. Umbilical and placental circulation remained intact, so the fetus was anesthetized through and maintained by the ewe (Bradley and Mistretta, 1973). Ewe and fetus, or postnatal lambs, were deeply anesthetized throughout experiments and received a lethal overdose of anesthetic at the end of experiments .…”

“…During the earlier period of accelerated growth of secondorder soma and dendrites, only low-frequency neural impulses are transmitted centrally through peripheral taste afferents (Bradley and Mistretta, 1973;Mistretta and Bradley, 1983). It is very difficult to record successfully from taste afferents younger than 100 days of gestation, and even at 110 days the magnitude of neural responses is small.…”

Chorda Tympani Responses to Gustatory Stimuli in Developing Rats

“…An electrophysiological study on the postnatal development of the gustatory system has also been thought necessary for full understanding of the ontogeny of gustatory function.However,neurophysiological studies on the development of taste receptors have been undertaken only by BRADLEY and MISTRETTA(1973),who found that the chorda tympani nerve responses to lingual stimulation by various taste substances in sheep fetuses aged 96 to 137 days are similar to those in lambs and adult sheep.…”

“…An electrophysiological study on the postnatal development of the gustatory system has also been thought necessary for full understanding of the ontogeny of gustatory function.However,neurophysiological studies on the development of taste receptors have been undertaken only by BRADLEY and MISTRETTA(1973),who…”

Approach to the fetal movements: a pilot study of six cases

“…A significant incre ase of the ingestion occurs when saccharin is injected in the amnion, and the opposite is detected on iodized oil, a bitter flavor. There f o re, the fetus has pre fe rence for sweet flavor and displeasure with the bitter flavor 10,11 .…”