Non-NMDA glutamate receptor antagonist injected into the hypothalamic paraventricular nucleus blocks the suckling stimulus-induced release of prolactin.
The aim of the present investigations was to test the involvement of the glutamatergic innervation of the hypothalamic paraventricular nucleus in the prolactin response to the suckling stimulus. A non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-dione disodium (CNQX), or an NMDA receptor antagonist, dizocipine hydrogen malate (MK-801), was injected bilaterally into the hypothalamic paraventricular nucleus of lactating freely moving rats before the end of a 4-h separation of the dams from their pups. The litters were then returned. Blood samples for prolactin were taken at different time points. The effect of the non-NMDA receptor antagonist was also tested in animals receiving the drug bilaterally into the dorsomedial nucleus area or the arcuate nucleus. Bilateral injection of CNQX into the paraventricular nucleus blocked the elevation in plasma prolactin concentration induced by the suckling stimulus. In contrast, bilateral administration of the NMDA receptor antagonist MK-801 into the paraventricular nucleus or bilateral injection of CNQX into the dorsomedial nucleus area or the arcuate nucleus did not interfere with the prolactin response to the suckling stimulus. The findings indicate that the glutamatergic innervation of the paraventricular nucleus is involved in the mediation of the neural signal of the suckling stimulus inducing prolactin release.
Bodnár
Ibolya
I
Neuroendocrine Research Laboratory, Department of Human Morphology & Developmental Biology, Hungarian Academy of Sciences and Semmelweis University, Tuzoltó u. 58, H-1094 Budapest, Hungary.
Bánky
Zsuzsanna
Z
Nagy
György M
GM
Halász
Béla
B
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D001111:Arcuate Nucleus of Hypothalamus / Q000187:drug effects / Q000378:metabolism; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004302:Dorsomedial Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism*; D008845:Microinjections; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects* / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D011388:Prolactin