Salsolinol induces a decrease in cyclic AMP at the median eminence and an increase at the adenohypophysis in lactating rats

Radnai, B; Kandár, Zoltán; Vı́gh, József; Mergl, Zsuzsa; Márk, Oláh; Fülöp, Ferenc; Vecsernyés, Miklós; Nagy, György M.

doi:10.1016/j.brainresbull.2004.11.007

Cited by 15 publications

(10 citation statements)

References 45 publications

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“…(2003) demonstrated that salsolinol binding sites are located both in the AP and ME, but the molecular structure of the salsolinol receptor has not been determined yet. Furthermore, the results of Radnai et al. (2005) suggest that salsolinol’s stimulating action is mediated by cyclic adenosine monophosphate.…”

Section: Discussionmentioning

confidence: 99%

The Possible Involvement of Salsolinol and Hypothalamic Prolactin in the Central Regulatory Processes in Ewes During Lactation

Górski¹,

Romanowicz²,

Herman

et al. 2009

Reproduction in Domestic Animals

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Salsolinol, a dopamine-related compound and prolactin-producing cells were found in the ovine hypothalamus. This study was designed to test the hypothesis that salsolinol, acting from the CNS level, is able to stimulate pituitary prolactin release as well as prolactin mRNA expression in the anterior pituitary cells (AP) and in the mediobasal hypothalamus (MBH) in lactating ewes. The intracerebroventricular infusions of salsolinol in two doses, total of 50 ng or 5 μg, were performed in a series of five 10-min infusions at 20-min intervals. All infusions were made from 12:30 to 15:00 and the pre-infusion period was from 10:00 to 12.30 h. The prolactin concentration in plasma samples, collected every 10 min, was determined by radioimmunoassay; prolactin mRNA expression in AP and MBH tissues was determined by real-time PCR. The obtained results showed that salsolinol infused at the higher dose significantly (p < 0.001) increased plasma prolactin concentration in lactating ewes, when compared with the concentration noted before the infusion and with that in lactating controls. In lactating ewes, the relative levels of prolactin mRNA expression in the AP and MBH were up to twofold and fivefold higher respectively than in non-lactating ewes (p < 0.05). In our experimental design, salsolinol did not significantly affect the ongoing process of prolactin gene expression in these tissues. We conclude that in ewes, salsolinol may be involved, at least, in the process of stimulation of prolactin release during lactation and that hypothalamic prolactin plays an important role in the central mechanisms of adaptation to lactation.

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Section: Discussionmentioning

confidence: 99%

The Possible Involvement of Salsolinol and Hypothalamic Prolactin in the Central Regulatory Processes in Ewes During Lactation

Górski¹,

Romanowicz²,

Herman

et al. 2009

Reproduction in Domestic Animals

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“…More recently, it has been shown that a cAMP-coupled mechanism is probably involved in the prolactin-releasing action of salsolinol at the level of lactotrophs (Randai et al 2005). In the current study, we hypothesized that salsolinol, as a putative neurotransmitter, was present in the infundibular nucleus IN/ME of lactating ewes and that its extracellular concentration in the IN/ME could increase in response to suckling stimulus in a manner similar to plasma concentration of prolactin.…”

Section: Introductionmentioning

confidence: 99%

Identification of salsolinol in the mediobasal hypothalamus of lactating ewes and its relation to suckling-induced prolactin and GH release

Misztal

Górski²,

Tomaszewska-Zaremba³

et al. 2008

Journal of Endocrinology

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The push-pull perfusions of the infundibular nucleus-median eminence (IN/ME) were made in lactating ewes (nZ7) 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.

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“…Parallel to the elevation of plasma PRL, SAL induces a significant decrease of cAMP concentration in the ME. In contrast, SAL injection results in a slight increase of cAMP at the level of the AL of the pituitary gland [49].…”

Section: Possible Physiological Role Of Salsolinolmentioning

confidence: 86%

Role of salsolinol in the regulation of pituitary prolactin and peripheral dopamine release

Olah

Bodnár

Daniel

et al. 2011

Reprod Medicine & Biology

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(R)-Salsolinol (SAL), a dopamine (DA)-related tetrahydroisoquinoline, has been found in extracts of the neuro-intermediate lobes (NIL) of pituitary glands and in the median eminence of the hypothalamus obtained from intact male rats and from ovariectomized and lactating female rats. Moreover, analysis of SAL concentrations in NIL revealed parallel increases with plasma prolactin (PRL) in lactating rats exposed to a brief (10 min) suckling stimulus after 4-h separation. SAL is sufficiently potent in vivo to account for the massive discharge of PRL that occurs after physiological stimuli (i.e. suckling). At the same time, it was without effect on the secretion of other pituitary hormones. It has been also shown that another isoquinoline derivative, 1-methyldihydroisoquinoline (1MeDIQ), which is a structural analogue of SAL, can dose-dependently inhibit the in-vivo PRL-releasing effect of SAL. Moreover, 1MeDIQ can inhibit the elevation of plasma PRL induced by physiological stimuli, for example suckling, or in different stressful situations also. 1MeDIQ also has a psycho-stimulant action, which is fairly similar to the effect of amphetamine, i.e. it induces an increase in plasma catecholamine concentrations. It is clear from these data that this newly discovered endogenous compound could be involved in regulation of pituitary PRL secretion. It has also been observed that SAL is present in peripheral, sympathetically innervated organs, for example the atrium, spleen, liver, ovaries, vas deferens, and salivary gland. Furthermore, SAL treatment of rats results in dosedependent and time-dependent depletion of the DA content of the organs listed above without having any effect on the concentration of norepinephrine. More importantly, this effect of SAL can be completely prevented by amphetamine and by 1MeDIQ pretreatment. It is clear there is a mutual interaction between SAL, 1MeDIQ, and amphetamine or alcohol, not only on PRL release; their interaction with catecholamine ''synthesis/metabolism'' of sympathetic nerve terminals is also obvious.

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Salsolinol induces a decrease in cyclic AMP at the median eminence and an increase at the adenohypophysis in lactating rats

Cited by 15 publications

References 45 publications

The Possible Involvement of Salsolinol and Hypothalamic Prolactin in the Central Regulatory Processes in Ewes During Lactation

The Possible Involvement of Salsolinol and Hypothalamic Prolactin in the Central Regulatory Processes in Ewes During Lactation

Identification of salsolinol in the mediobasal hypothalamus of lactating ewes and its relation to suckling-induced prolactin and GH release

Role of salsolinol in the regulation of pituitary prolactin and peripheral dopamine release

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