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This Article Full Text Full Text (PDF) All Versions of this Article: JOE-07-0640v1 198/1/83    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Misztal, T. Articles by Romanowicz, K. PubMed PubMed Citation Articles by Misztal, T. Articles by Romanowicz, K.

Departments of¹ Endocrinology² Neuroendocrinology, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, 05-110 Jablonna n/Warsaw, Poland³ Department of Sheep and Goat Breeding, Agricultural University in Cracow, Mickiewicza 24/28 Street, 30-059 Cracow, Poland

(Correspondence should be addressed to T Misztal; Email: t.misztal{at}ifzz.pan.pl)

The push–pull perfusions of the infundibular nucleus–median eminence (IN/ME) were made in lactating ewes (n=7) twice, to identify dopamine (DA)-derived salsolinol and the changes in its extracellular concentration in response to suckling. The perfusate collecting period in every ewe consisted of control non-suckling period, 1000–1230 h (five perfusates), and suckling period, 1230–1500 h (next five perfusates). Simultaneously, blood samples were collected from 1000 to 1500 h at 10-min intervals. The perfusate concentrations of salsolinol and DA were measured by HPLC, and plasma prolactin and GH concentrations were assayed by the RIA. Mean concentrations of salsolinol in perfusates collected from the anterior and posterior parts of the IN/ME (according to post-mortem localization of a perfusion site) increased significantly (P<0.05 and P<0.001 respectively) during the suckling period, when compared with those noted during the non-suckling period. While no DA was found in the anterior part, only vestigial amounts of DA were found in a few perfusates collected from the posterior part. Salsolinol was not detected in the IN/ME of ewes 10 weeks after weaning (seasonal anoestrus). Mean plasma prolactin and GH concentrations during suckling were significantly (P<0.001) higher than those noted during the non-suckling period. In conclusion, our current study reveals that salsolinol is present in the IN/ME of lactating ewes and that its extracellular concentration increases during suckling. Moreover, it supports the role of salsolinol as a neurotransmitter involved in the regulatory process of prolactin secretion at least during lactation.