...Gisela Erika Pennacchio; Carolina Ayala; María Belén Sanchez; María Tamara Moreno-Sosa; Fiorella Campo-Verde-Arbocco; Graciela Alma Jahn; Susana Ruth Valdez; Marta Soaje Introduction: OFA hr/hr rats have deficient lactation with impaired suckling-induced PRL release. Unlike their background strain...

... suckling is a potent stimulus for the secretion of these three hormones, we investigated the mediating role of neuronal histamine in suckling-induced release of oxytocin, PRL and ACTH in conscious lactating rats. The animals were pretreated with the histamine synthesis inhibitor α-fluoromethylhistidine...

... hybridization, lactation-induced changes in NPY and POMC gene expression throughout the ARC. In a second phase of the study, we attempted to determine whether any relationship exists between neuropeptide gene expression and the suckling stimulus itself. For this, we used experimental groups of animals submitted...

... of suckling in lactating rats is mediated by oxytocinergic mechanisms. Male rats were given oxytocin in doses of 2 or 20 ng (SC) or 2 or 200 ng (ICV). Trunk blood was collected and hormone analysis performed by radioimmunoassay. Subcutaneous injections of oxytocin increased insulin, glucagon and glucose...

... by suckling. It has been suggested that proto-oncogene transcription factors such as Fos/Jun act as early nuclear transducers of sensory stimuli in neurons. Therefore, we have studied with immunohistochemistry Fos-related antigens (FRAs) as a marker for neuronal activity in the PVN and SON during suckling...

... elevation in their plasma PRL levels although both interventions increased blood corticosterone concentrations. Lactating mothers receiving formalin after a 30-min suckling stimulus preceded by 4 h isolation did not show appreciable changes in pituitary PRL secretion following the administration of formalin...

... vasopressin release failed to change within the 90-min period following osmotic stimulation. In conscious lactating rats, suckling increased oxytocin contents in microdialysates sampled simultaneously in blood and the supraoptic nucleus (p < 0.05 each) further validating the microdialysis techniques used...

...Maria Uribe; Luis Redondo; Jean-Louis Charli; Patricia Joseph-Bravo Thyrotropin releasing hormone (TRH) is released from the median eminence in response to neural stimuli evoked by different physiologic conditions (i.e. cold stress or suckling). The paraventricular nucleus (PVN) synthesizes pro-TRH...

...György M. Nagy; Tamäs J. Görcs; Béla Halász To investigate the role of vasopressin in prolactin (PRL) release during lactation, vasopressin antiserum (VP-Ab) was administered to lactating rats, giving it intravenously 15 min before permitting their previously isolated pups to suckle...

... situations when prolactin (PRL) secretion is stimulated (suckling) or inhibited (pup separation). In addition VIP levels in blood plasma were determined in both situations. Acute suckling induced changes in VIP concentration only in the rostral part of the anterior hypothalamic (rAHN) and the paraventricular...

...Maud Eriksson; Kerstin Uvnäs-Moberg The aim of the present study was to measure plasma levels of vasoactive intestinal polypeptide (VIP) and oxytocin following suckling, electrical stimulation of the mammary nerve and oxytocin infusion in lactating rats. Trunk blood was collected by decapitation...

...Jan M.M. Rondeel; Wim J. De Greef; Theo J. Visser; James L. Voogt The present study was concerned with the effect of suckling on the hypothalamic release of thyrotropin-releasing hormone (TRH), dopamine and adrenaline in lactating rats as estimated by push-pull perfusion of the median eminence...

...Michael Selmanoff; Karen A. Gregerson The role that opiate peptides play in suckling-induced prolactin (PRL) release was examined in 10-day post-partum lactating rats. The opiate receptor antagonist naloxone (NAL) suppressed suckling-induced PRL release in a dose-dependent manner and a large dose...

...Philip G. Knight; Colin M. Howles; Francis J. Cunningham A pharmacological approach was used to study the involvement of opioid peptides and dopamine in mediating the suckling-induced release of prolactin in the lactating ewe (10–20 days post partum). To promote reliable and predictable suckling...

... from their pups 4 h earlier, and mothers separated from their pups 4 h earlier, after which the pups were allowed to suckle for 5 or 30 min. In spite of the acute changes in circulating prolactin, 5-HT levels in the median eminence were not affected in any situation studied. These results suggest...

...-acetic acid (5-HIAA)] were measured in the suprachiasmatic (SCN), medial preoptic (MPO), and arcuate (AN) nuclei as well as the median eminence (ME) and striatum (ST) of the rat brain and correlated with changes in serum prolactin resulting from restraint stress (30 min) or the stimulus of acute suckling...

...Clark E. Grosvenor The storage form of prolactin (PRL) was converted into the releasable form in the lactating rat pituitary gland within 10 min of suckling by 6 pups following 4–5 h of nonsuckling on postpartum day 13–14. The characteristics of the PRL discharge from the releasable pool...

...Michael D. Culler; Newell H. McArthur; William L. Dees; Robert E. Owens; Paul G. Harms Suckling has been demonstrated to impair the release of pituitary luteinizing hormone (LH) and to prevent the dramatic increase in plasma LH observed following ovariectomy. In the present study, the effect...

... were measured to indicate their synthetic activity. When a normal suckling stimulus was applied only after a delay of 7 days post-partum the nucleolar changes in PV and SO neurones that followed were similar to those that occur normally when a litter is suckled from birth; these changes thus do...

... stimulation (vago-pituitary reflex), (c) suckling (milk-ejection reflex). Moreover, we examined the effect of a dopaminergic agonist, apomorphine, on the milk-ejection (ME) reflex. I.c.v. injection of 20 μg haloperidol inhibited the vaginal and vagal reflexes. The inhibition of the ME reflex produced by 2, 5...