The Reticulo—hypothalamic Pathway Controlling the Release of Oxytocin in the Ewe

Abstract

The pathways of the milk-ejection reflex in the ewe have been described at the spinal and mesencephalic levels (Richard, 1970;Richard, Urban & Denamur, 1970). The present paper describes the pathways followed by impulses of mammary and vaginal origin between the mesencephalic reticular formation and the neurohypophysis.In the anaesthetized ewe the thalamus is not necessary for the transfer of impulses to the neurohypophysis as shown by studying the electrical activities evoked in the pituitary stalk by mammary or vaginal stimulation. These impulses follow a subthalamic pathway through the medial forebrain bundle. In conscious ewes small areas of coagulations in the pathways did not block the milk-ejection reflex during milking because the fibres are diffuse at all levels of the central nervous system. Larger lesions result in non-specific effects which interrupt milk secretion.Supra-diencephalic structures are not necessary for the milk-ejection reflex.

Factors affecting milk ejection and removal during milking and suckling of dairy cows

“…The neural component starts by the stimulation of the neural receptors primarily located in the tip of the teats (Lefcourt and Akers, 1984). The neural system carries the impulses from these receptors to the brain, especially to the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus (Richard, 1972). These nuclei are clusters of the nerve cell bodies that are able to synthesize the nonapeptide hormone oxytocin, which moves, attached to a carrier protein (neurophysin I), through the pituitary stalk via the nerve cell axons.…”

Μελετη Της Ανατομικης Οργανωσης Του Ανιοντος Σκελους Του Νευρορμονικου Αντανακλαστικου Της Καθοδου Του Γαλακτος Στο Προβατο

“…(1969) και Aulsebrook και Holland (1969α,β) στο κουνέλι. Τέλος, ο Richard (1972) απέδειξε ότι το ανιόν σκέλος του αντανακλαστικού ακολουθεί πορεία μέσω της έσω τηλεγκεφαλικής δεσμίδας και ότι οι πυρήνες του θαλάμου δεν αποτελούν σταθμό της οδού αυτής.…”