[Attempted interpretation of water injected into the inguinal artery on the augmentation of intramammary pressure of the sheep].
The increase in intramammary pressure caused by injecting small amounts of water into the udder artery of anesthetized ewes does not seem to be a nervous reaction induced by the stimulation of sensitive mammary receptors: the deflections remain unchanged after complete denervation of the gland (fig. 4) and after the injection of water at different temperatures (4 to 37 degrees C; fig. 1) or pH's (4.6 to 9.8; fig. 2). Since injecting the same volumes of blood (fig. 3), isotonic NaCl (fig. 5) or glucose (fig. 6) solutions does not cause the intramammary pressure to increase, water effect would appear to result from a change in blood osmotic pressure. Among the substances released when the blood corpuscles or platelets are destroyed, kallikrein and histamine do not seem to play a role. These products induce intramammary pressure to rise (fig. 7, 9) but latency and duration are longer than with water Also, their respective inhibitors, aprotinin and phenergan, always block their effect on intramammary pressure but not that of water. On the other hand, water and bradykinin (fig. 8) produce similar responses, indicating that the latter substance may play a role. We must consider also the possible action of extra-capillary water transfer, modifying ion flux and myoepithelial cell membrane potential or simply inducing the alveolar cells to swell and the acini to flatten. This last hypothesis permits a better interpretation of the pressure decreases noted after injection of hypertonic solutions (figs. 5, 6) since reverse water movements would have the opposite effect.
D000818:Animals; D001158:Arteries; D001920:Bradykinin / Q000494:pharmacology; D005260:Female; D005947:Glucose / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D007610:Kallikreins / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000098:blood supply / Q000187:drug effects / Q000502:physiology*; D009994:Osmolar Concentration; D011312:Pressure; D012756:Sheep; D012965:Sodium Chloride / Q000494:pharmacology; D014867:Water / Q000494:pharmacology*
D014867:Water; D012965:Sodium Chloride; D006632:Histamine; D007610:Kallikreins; D005947:Glucose; D001920:Bradykinin
Essai d'interprétation de l'action de l'eau injectée dans l'artère inguinale sur l'augmentation de pression intramammaire de la brebis.