Blockade of the Ferguson reflex by lumbar epidural anaesthesia in the parturient sheep: effects on oxytocin secretion and uterine venous prostaglandin F levels

The role of oxytocin in the increase in utero-ovarian venous prostaglandin F (PGF) level caused by vaginal distension was investigated by using lumbar epidural anaesthesia to block the oxytocin secretion reflex. Whereas vaginal distension raised jugular venous oxytocin and utero-ovarian venous PGF levels in untreated sheep, neither response occurred after lumbar anaesthesia. Lumbar anaesthesia had no effect on the rise in utero-ovarian venous PGF level caused by administered oxytocin. These findings support the suggestion that a reflex release of oxytocin is involved in the elevation of utero-ovarian venous PGF observed after vaginal distension in parturient sheep

Temporal relationship between changes in oxytocin and prostaglandin F levels in response to vaginal distension in the pregnant and puerperal ewe

To investigate the role of oxytocin in the increase in utero ovarian venous prostaglandin F (PGF) level caused by vaginal distension, jugular venous oxytocin and utero ovarian venous PGF were measured simultaneously in one sheep in late pregnancy and in one sheep shortly before parturition. Vaginal distension raised oxytocin and PGF levels in both animals and oxytocin levels increased before those of PGF. These findings support the suggestion that the elevated PGF levels resulting from vaginal distension are caused by the reflex secretion of oxytocin

Interleukin-1beta and interleukin-6 stimulate neurohypophysial hormone release in vitro

Interleukin-1 (IL-1) and interleukin-6 (IL-6) have been reported to stimulate the release of corticotrophin-releasing hormone (CRH) in vitro, the response being antagonized by the cyclo-oxygenase inhibitor, indomethacin. The effects of cytokines on the other major ACTH-releasing hormone, vasopressin (AVP), and the other neurohypophysial hormone, oxytocin, have been little studied, and the published data are conflicting. We have therefore used a previously validated rat hypothalamic explant model to evaluate whether IL-1 beta and IL-6 can directly activate the AVP and oxytocin neurosecretory system. In addition, we have also investigated the effects of inhibition of cyclo-oxygenase (CO) and lipoxygenase (LO) activities on the stimulated release of AVP and oxytocin by means of a series of antagonists, including a specific LO pathway inhibitor. It was found that IL-1 beta produced a dose-dependent increase in the release of AVP and oxytocin at doses of 10 and 100 U/ml (P < 0.005). Only at the higher dose of 100 U/ml was IL-6 able to increase significantly AVP and oxytocin release (P < 0.05). These stimulatory effects of IL-1 beta and IL-6 were blocked by cyclo-oxygenase inhibitors, indomethacin (28 microM) and ibuprofen (100 nM), but not by the lipoxygenase inhibitor, BW A4C (10 micrograms/ml), suggesting that prostaglandins are involved in this process

Gaseous transmitters as new agents in neuroendocrine regulation

Review su dati originali personali sul ruolo che i nuovi neurotrasmettitori gassosi, NO e CO, svolgono nel sistema nervoso centrale, modulando il rilascio ipotalamico di importanti neuropeptidi quali il CRH e la vasopressina, ed intervenendo nei processi di comunicazione neuroimmunoendocrina

Differential effects of neuroexcitatory aminoacids on CRH-41 and vasopressin release from rat hypothalamic explants

Studio sull'effetto degli aminoacidi eccitatori NMDA, kainato e quisqualato sul rilascio di CRH da espianti di ipotalamo di ratto in vitro, e suo significato nella regolazione neuroendocrin

Melatonin and its analogs inhibit the basal and stimulated release of hypothalamic vasopressin and oxytocin in vitro

Studio dell'effetto della melatonina e suoi analoghi sul rilascio di ossitocina e vasopressina in un modello di espianti di ipotalamo in vitro: i dati indicano un effetto inibitorio sul rilascio dei due ormoni, sia in consizioni basali che sotto stimolazione con KC