Septal-preoptic unit responses to microelectrophoresis of cholecystokinin, gastrin, vasoactive intestinal peptide and secretin in the rat

Akema, Tatsuo; Praputpittaya, Chucheep; Kimura, Fukuko

doi:10.1016/0006-8993(86)91084-x

Cited by 10 publications

(3 citation statements)

References 30 publications

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“…In the hypothalamus, VIP has been shown to stimulate adenylate cyclase activity (Quw et al, 1978;BORGHI et al, 1979) and alter neuronal electrical activity (HASKINS et al, 1982;AKEMA et al, 1986). When injected in the third ventricle, VIP affects the anterior pituitary hormone secretion, probably acting at the hypothalamus (VIJAYAN et a!., 1979;ALEXANDER et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

Time-dependent effects of intrahypothalamic injection of vasoactive intestinal peptide on spontaneous motor activity in rats.

1989

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In male Wistar rats, microinjection cannulae were stereotaxically implanted in the ventromedial and paraventricular hypothalamic nuclei. After control recordings of spontaneous motor activity for 4-6 days, vasoactive intestinal peptide (VIP) was injected in a dose of 1.0 pg and a volume of 2.0 pl into these nuclei at 1100 or 1900h, and the activity during the 3-h period following was compared with that on the control days in individual animals. VIP injection produced an increase when injected at 1100 h, and a decrease when injected at 1900 h. Thus, a timedependent fluctuation in the VIP effect on the hypothalamic neuronal activity was suggested.

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Section: Discussionmentioning

confidence: 99%

Time-dependent effects of intrahypothalamic injection of vasoactive intestinal peptide on spontaneous motor activity in rats.

1989

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“…The animals, hormonal conditions and electrophysiological tcchniques used were similar to those in our previous neuroendocrinological (4) and electrophysiological experiments (7). In brief, female Wistar rats, ovariectomized 3 to 4 weeks before the experiment, were either hormonally unprimed or prinied with oestradiol benzoate (5 pg, injected sc at noon 3 days before the experiment).…”

Section: Methodsmentioning

confidence: 99%

Preoptic Unit Responses to Microelectrophoresis of Neurotensin and its Antiserum in Female Rats

Akema

Kimuraf

1990

J Neuroendocrinology

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We and other investigators have demonstrated the stimulation of luteinizing hormone secretion following the microinjection of neurotensin (NT) into the medial preoptic area in female rats. The present study electrophysiologically examined the action of the peptide in the same brain region. Microelectrophoresis of NT produced either excitation or inhibition in 24% of the medial preoptic neurons tested in oestrogen-primed and unprimed ovariectomized animals. Effective blockade of NT-induced excitatory and inhibitor unit responses by means of the simultaneous application of an antiserum to NT (anti-NT) indicated that they were produced by specific actions of the peptide. In addition, anti-NT by itself altered the spontaneous firing rate in some NT-responsive cells. These findings are in accord with the hypothesis that the preoptic area is a site of the action of NT in the female rat.The medial preoptic area comprises neurons containing luteinizing hormone-releasing hormone (LHRH) (1) and is widely accepted as a regulatory center for luteinizing hormonc (LH) secretion in the female rat. Evidence has been accumulated showing that neurotensin (NT), a tridecapeptide first identified in the bovine hypothalamus (2), is one of the neuromodulators which regulate the activity of this center to affect the hormone secretion. Microinjection of NT into the medial preoptic area significantly enhanced LH secretion in anesthetized female rats (3) and in conscious ovariectomized oestrogen-primed rats (4). The peptide therefore probably acts directly in the preoptic and/or adjacent areas which contain NT-related neural elements (3,5). A recent finding that a series of basal forebrain injections with an antiserum to NT reduced the magnitude of the steroid-induced surge of LH in the ovariectomized rat (6) further supports this hypothesis. The aim of the present study was to electrophysiologically examine the relevance of the preoptic area as a site of NT action in female rats. The specificity of the unit response was verified with a specific antiserum to NT.

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“…Secretin, when injected into the preoptic region of the ovariectomized estrogen primed rat, was strikingly effective in increasing the circadian rise in luteinizing hormone (LII) and prolactin (PRL) secretion (Kimura et al, 1987). This peptide predominantly inhibited unit activity in the preoptic region (Akema et al, 1986). In those experiments, injection of vasoactive intestinal peptide (VIP) completely abolished the occurrence of circadian rise in LII secretion, whereas the injection of peptide histidine isoleucine (PHI) facilitated it.…”

Section: Introductionmentioning

confidence: 94%

Effects of Preoptic Injection of Glucagon on Luteinizing Hormone Secretion in Ovariectomized Rats with or without Estrogen Priming

Mitsugi¹,

Hashimoto²,

Yoshida³

et al. 2009

Exp Clin Endocrinol Diabetes

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Effects of microinjection of glucagon or GIP into the medial preoptic area on luteinizing hormone (LH) and prolactin (PRL) release were examined in unanesthetized ovariectomized rats with or without estrogen priming. Microinjection of glucagon (1.0 microgram) into the medial preoptic area of ovariectomized estrogen-primed rats significantly facilitated the circadian afternoon rise in LH secretion as compared to the hormone values in control animals microinjected with physiological saline. The timing of the afternoon LH rise was not altered by glucagon and the circadian rise of PRL secretion was not altered by glucagon injected in the preoptic area. The injection of GIP did not have any significant effect on either LH or PRL secretion. In ovariectomized estrogen-unprimed rats, on the other hand, glucagon did not affect the pulsatile LH secretion, but it inhibited PRL secretion. GIP did not affect any hormone secretion. The results show that (1) glucagon, as other secretion family peptides such as secretion and PHI, can stimulate the preoptic LH secretory mechanism that undergoes the circadian clock mechanism under the influence of estrogen, and (2) without estrogen priming, glucagon in the preoptic area inhibits PRL secretion.

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Septal-preoptic unit responses to microelectrophoresis of cholecystokinin, gastrin, vasoactive intestinal peptide and secretin in the rat

Cited by 10 publications

References 30 publications

Time-dependent effects of intrahypothalamic injection of vasoactive intestinal peptide on spontaneous motor activity in rats.

Time-dependent effects of intrahypothalamic injection of vasoactive intestinal peptide on spontaneous motor activity in rats.

Preoptic Unit Responses to Microelectrophoresis of Neurotensin and its Antiserum in Female Rats

Effects of Preoptic Injection of Glucagon on Luteinizing Hormone Secretion in Ovariectomized Rats with or without Estrogen Priming

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