Effects of ovariectomy on inputs from the medial preoptic area to the ventromedial nucleus of the hypothalamus of young adult rats

2020 ◽  
Author(s):  
Laís da Silva Pereira ◽  
Denise Ribeiro Gobbo ◽  
Jozélia Gomes Pacheco Ferreira ◽  
José de Anchieta de Castro e Horta‐Junior ◽  
Susana Isabel Sá ◽  
...  
Keyword(s):  
Young Adult ◽  
Preoptic Area ◽  
Medial Preoptic Area ◽  
Ventromedial Nucleus ◽  
Adult Rats

Varying sensitivity to the negative oestrogen feedback during the ovarian cycle of female rats: evidence for the involvement of oestrogen and the medial preoptic area

1984 ◽  
Vol 102 (3) ◽  
pp. 287-294 ◽  
Author(s):  
F. Döcke ◽  
W. Rohde ◽  
P. Gerber ◽  
R. Chaoui ◽  
G. Dörner
Keyword(s):  
Preoptic Area ◽  
Medial Preoptic Area ◽  
Ovarian Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Adult Rats ◽  
Gonadotrophin Secretion ◽  
Arcuate Region ◽  
Lh Secretion ◽  
Follicle Maturation

ABSTRACT The gonadotrophic response to a single injection of oestradiol benzoate (OB) was studied in acutely ovariectomized adult rats during the different stages of a 4-day ovarian cycle. The results showed a sudden decline of the sensitivity to the gonadotrophin-inhibiting effect of OB between metoestrus and dioestrus. This desensitization to the negative oestrogen feedback was probably caused by an oestrogen action on the medial preoptic area (MPOA). In rats ovariectomized and implanted with OB in the MPOA in metoestrus, an s.c. injection of OB on the presumptive day of pro-oestrus did not lower the circulating LH and FSH levels, whereas a clear suppression of gonadotrophin secretion was seen in females implanted with cholesterol in the MPOA or implanted with OB in the hypothalamic ventromedial–arcuate region. Similar findings were obtained in rats which had been ovariectomized 3–4 weeks before implantation. A final experiment demonstrated that bilateral lesioning of the MPOA also reduced the sensitivity to the negative feedback action of oestrogen in long-term ovariectomized rats. In all experiments performed, diminution of the oestrogen-induced inhibition of LH secretion was more marked than that of suppression of FSH secretion. It is proposed that desensitization to the negative oestrogen feedback, probably resulting from an inhibitory oestrogen action on medial preoptic neurones, is a prerequisite for adequate gonadotrophic support of preovulatory follicle maturation in the presence of a continuously rising oestrogen concentration in the blood. J. Endocr. (1984) 102, 287–294

Effects of ovariectomy on the inputs from the medial nucleus of the amygdala to the ventromedial nucleus of the hypothalamus in young adult rats

2021 ◽  
Vol 746 ◽  
pp. 135657
Author(s):  
Denise Ribeiro Gobbo ◽  
Lais da Silva Pereira ◽  
Jozélia Gomes Pacheco Ferreira ◽  
José Anchieta de Castro Horta-Junior ◽  
Jackson Cioni Bittencourt ◽  
...  
Keyword(s):  
Young Adult ◽  
Ventromedial Nucleus ◽  
Adult Rats ◽  
Medial Nucleus

scholarly journals Hypertension in Prenatally Undernourished Young-Adult Rats Is Maintained by Tonic Reciprocal Paraventricular–Coerulear Excitatory Interactions

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3568
Author(s):  
Bernardita Cayupe ◽  
Carlos Morgan ◽  
Gustavo Puentes ◽  
Luis Valladares ◽  
Héctor Burgos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Young Adult ◽  
Binding Sites ◽  
Systolic Pressure ◽  
Adult Rats ◽  
Excitatory Pathways ◽  
Induced Hypertension ◽  
Prenatal Undernutrition ◽  
Number Of Cells

Prenatally malnourished rats develop hypertension in adulthood, in part through increased α1-adrenoceptor-mediated outflow from the paraventricular nucleus (PVN) to the sympathetic system. We studied whether both α1-adrenoceptor-mediated noradrenergic excitatory pathways from the locus coeruleus (LC) to the PVN and their reciprocal excitatory CRFergic connections contribute to prenatal undernutrition-induced hypertension. For that purpose, we microinjected either α1-adrenoceptor or CRH receptor agonists and/or antagonists in the PVN or the LC, respectively. We also determined the α1-adrenoceptor density in whole hypothalamus and the expression levels of α1A-adrenoceptor mRNA in the PVN. The results showed that: (i) agonists microinjection increased systolic blood pressure and heart rate in normotensive eutrophic rats, but not in prenatally malnourished subjects; (ii) antagonists microinjection reduced hypertension and tachycardia in undernourished rats, but not in eutrophic controls; (iii) in undernourished animals, antagonist administration to one nuclei allowed the agonists recover full efficacy in the complementary nucleus, inducing hypertension and tachycardia; (iv) early undernutrition did not modify the number of α1-adrenoceptor binding sites in hypothalamus, but reduced the number of cells expressing α1A-adrenoceptor mRNA in the PVN. These results support the hypothesis that systolic pressure and heart rate are increased by tonic reciprocal paraventricular–coerulear excitatory interactions in prenatally undernourished young-adult rats.

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