Involvement of prolactin in the REM sleep-promoting activity of systemic vasoactive intestinal peptide (VIP).
The involvement of pituitary prolactin (PRL) in systemic vasoactive intestinal peptide (VIP)-induced sleep was studied. Male rats were implanted with electrodes for EEG-recording, with brain thermistors to record cortical temperature (Tcrt) and with chronic intracardial catheters to obtain blood samples and to deliver substances. One group of rats (n = 8) received normal rabbit serum (NS)+physiological saline (SAL) on the baseline day and was injected with NS+VIP on the experimental day. In the other group of rats (n = 6), the baseline day was followed by administration of PRL-antiserum (PRL-AS) + VIP on the experimental day. The sera and VIP or SAL were injected 30 min before and at light onset, respectively. Sleep-wake activity was then recorded for the next 12-h light period. Systemic VIP-stimulated PRL secretion as measured by RIA in serial samples obtained hour 1 postinjection. VIP also elicited selective increases in REM sleep (REMS) in the rats pretreated with NS. Tcrt was not affected by VIP. Administration of PRL-AS blocked the increase in circulating levels of free (non-IgG-bound) PRL and prevented VIP-enhanced REMS. Comparisons of the sleep effects of PRL-AS+VIP with the previously reported changes in sleep after PRL-AS alone indicate that PRL has a major role in the mediation of the REMS-promoting activity of systemic VIP. The results suggest that an increased release of endogenous pituitary PRL modulates REMS.
Obál
F
F
Department of Physiology, Albert Szent-Györgyi Medical University, Szeged, Hungary.
Payne
L
L
Kacsoh
B
B
Opp
M
M
Kapás
L
L
Grosvenor
C E
CE
Krueger
J M
JM
D000818:Animals; D001831:Body Temperature; D004569:Electroencephalography; D007106:Immune Sera / Q000276:immunology; D008297:Male; D009994:Osmolar Concentration; D011388:Prolactin / Q000097:blood / Q000276:immunology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects; D012895:Sleep, REM / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D007106:Immune Sera; D014660:Vasoactive Intestinal Peptide; D011388:Prolactin