NMDA receptor antagonists reduce restraint-induced release of prolactin in male rats.
OBJECTIVE
To investigate the effects of N-methyl-D-aspartate (NMDA) receptor antagonists on restraint-induced release of prolactin (PRL) in male Wistar rats of different ages.


METHODS
Rats were implanted with a brain ventricular for icv injection, and with a jugular vein cannula for iv injection. Competitive NMDA receptor antagonist AP-5 and noncompetitive NMDA receptor blocker MK-801 was injected via brain cannula or vein cannula and was restrained for 3 hours. The blood sample was collected through vein cannula during the restraint. The plasma concentration of prolactin was measured by RIA.


RESULTS
The restraint-induced PRL release in the adult rat (12-weeks) was significantly suppressed by MK-801 (50 microg/rat, icv; or 5 mg/kg, iv) and was partially inhibited by pretreatment of AP-5 (50, 100 microg/rat, icv), but was not changed by systemic administration of AP-5 (10 mg/kg, iv). MK-801 (5 mg/kg, iv) prevented the restraint-induced PRL release in the peripuberal rat (45-days) and in the middle-aged rat (16-months).


CONCLUSIONS
Central NMDA receptors mediate restraint-induced PRL release in the male rat.
Liu
Jian-Xiang
JX
Division of Neurobiology and Physiology, College of Life Sciences, Yuquan Campus, Zhejiang University, Hangzhou 310027, People's Republic of China.
Du
Ji-Zeng
JZ
Asai
Sayaka
S
Shi
Zhan-Quan
ZQ
Watanabe
Gen
G
Taya
Kazuyoshi
K
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000378:metabolism*
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; D015763:2-Amino-5-phosphonovalerate; D011388:Prolactin