Systemic Leptin Increases the Electrical Activity of Supraoptic Nucleus Oxytocin Neurones in Virgin and Late Pregnant Rats

2013 ◽  
Vol 25 (4) ◽  
pp. 383-390 ◽  
Author(s):  
S. Velmurugan ◽  
J. A. Russell ◽  
G. Leng
Keyword(s):  
Electrical Activity ◽  
Supraoptic Nucleus ◽  
Pregnant Rats ◽  
Oxytocin Neurones

Relaxin increases the firing rate of supraoptic neurones and increases oxytocin secretion in the rat

1992 ◽  
Vol 132 (1) ◽  
pp. 149-158 ◽  
Author(s):  
S. A. Way ◽  
G. Leng
Keyword(s):  
Electrical Activity ◽  
Firing Rate ◽  
Supraoptic Nucleus ◽  
Ovariectomized Rats ◽  
Milk Ejection ◽  
Independent Mechanism ◽  
Stimulus Secretion Coupling ◽  
Milk Ejection Reflex ◽  
Oxytocin Neurones ◽  
Sustained Increase

ABSTRACT In urethane-anaesthetized ovariectomized rats, injection of porcine relaxin (7·5 and 15 μg/kg, i.v.) caused a sustained increase in circulating plasma oxytocin and vasopressin concentrations; 10 μg relaxin/rat i.v. produced a smaller but significant increase in plasma oxytocin concentration in conscious ovariectomized rats. A significant increase in oxytocin concentration and inhibition of the spontaneous milk-ejection reflex was also seen in anaesthetized (ovary intact) lactating rats following injection of relaxin (7·5 μg/kg, i.v.). To investigate whether relaxin acts by increasing the electrical activity of oxytocin neurones or by facilitating stimulus-secretion coupling in the pituitary, the electrical activity of neurones in the supraoptic nucleus was recorded in urethane-anaesthetized lactating rats and in ovariectomized rats. Porcine relaxin (10 μg/rat, i.v.) increased the firing rate of both oxytocin and vasopressin neurones in the supraoptic nucleus in lactating rats. The response to relaxin was unaffected by subsequent injection of naloxone (1 mg/kg, i.v.). Oxytocin neurones were also activated by injection of relaxin (10 μg/rat) into ovariectomized rats. Combining the electrophysiological data, the neuronal activation following relaxin was significantly correlated with the level of spontaneous activity prior to relaxin injection. The results show that relaxin acts centrally to increase circulating plasma oxytocin and vasopressin concentrations by an opioid-independent mechanism. Journal of Endocrinology (1992) 132, 149–158

Role of oxytocin in activation of spontaneous electrical activity of uterine body and uterine tubes in non-pregnant rats

2011 ◽  
Vol 47 (3) ◽  
pp. 284-291 ◽  
Author(s):  
K. V. Kazaryan ◽  
N. G. Hunanyan ◽  
I. B. Meliksetyan ◽  
R. R. Hakopyan ◽  
A. A. Saakyan
Keyword(s):  
Electrical Activity ◽  
Pregnant Rats ◽  
Spontaneous Electrical Activity ◽  
Uterine Body

Changes in the electrical activity of locus coeruleus neurons in pregnant rats

1988 ◽  
Vol 85 (3) ◽  
pp. 329-332 ◽  
Author(s):  
S. Nakamura ◽  
T. Sakaguchi ◽  
T. Shirokawa ◽  
A. Yamatodani ◽  
K. Maeyama ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Locus Coeruleus ◽  
Pregnant Rats

scholarly journals Effects of vasopressin on electrical activity in the guinea-pig supraoptic nucleus in vitro.

1983 ◽  
Vol 33 ◽  
pp. 151
Author(s):  
Nobukuni Ogata ◽  
Hidehiko Abe ◽  
Tadashi Matsuo ◽  
Masumi Inoue
Keyword(s):  
Guinea Pig ◽  
Electrical Activity ◽  
Supraoptic Nucleus

Effect of progesterone on the activation of neurones of the supraoptic nucleus during parturition

Reproduction ◽  
2000 ◽  
pp. 367-376 ◽  
Author(s):  
IA Antonijevic ◽  
JA Russell ◽  
RJ Bicknell ◽  
G Leng ◽  
AJ Douglas
Keyword(s):  
Progesterone Receptor ◽  
Supraoptic Nucleus ◽  
Late Pregnancy ◽  
Endogenous Opioids ◽  
Opioid Antagonist ◽  
Endogenous Opioid ◽  
Fos Expression ◽  
Oxytocin Neurones ◽  
Supraoptic Nuclei

Parturition is driven by a pulsatile pattern of oxytocin secretion, resulting from burst firing activity of supraoptic oxytocin neurones and reflected by induction of Fos expression. Rats were injected with progesterone on day 20 of pregnancy to investigate the role of the decreasing progesterone:ratio oestrogen ratio, which precedes delivery, in the activation of supraoptic neurones. Progesterone delayed the onset of birth by 28 h compared with vehicle (control) and prolonged the duration of delivery, which was overcome by pulsatile injections of oxytocin, indicating that the slow delivery may reflect impaired oxytocin secretion. Parturient rats pretreated with progesterone had fewer Fos immunoreactive nuclei in the supraoptic nucleus than did parturient rats pretreated with vehicle. The number of Fos immunoreactive nuclei was not restored after oxytocin injection, indicating that appropriate activation of oxytocin neurones is impaired by progesterone and also that there is a lack of stimulatory afferent drive. Fos expression increased in the nucleus of the tractus solitarius during parturition in rats pretreated with either vehicle or progesterone, but not in rats that had been pretreated with progesterone and induced with oxytocin, indicating that this input was inhibited. Endogenous opioids inhibit oxytocin neurones in late pregnancy and the opioid antagonist, naloxone, increases Fos expression in supraoptic nuclei by preventing inhibition. However, progesterone attenuated naloxone-induced Fos expression in the supraoptic nucleus in late pregnancy and naloxone administered during parturition did not accelerate the duration of births delayed by progesterone administration, indicating that progesterone does not act by hyperactivation of endogenous opioid tone. RU486, a progesterone receptor antagonist, enhanced supraoptic neurone Fos expression in late pregnancy, indicating progesterone receptor-mediated actions. Thus, progesterone withdrawal is necessary for appropriate activation of supraoptic and tractus solitarius neurones during parturition.

Effect of stimulatory and inhibitory drugs on uterine electrical activity measured noninvasively from the abdominal surface of pregnant rats

2000 ◽  
Vol 183 (1) ◽  
pp. 68-75
Author(s):  
Catalin S. Buhimschi ◽  
George R. Saade ◽  
Irina A. Buhimschi ◽  
Remzi Gokdeniz ◽  
Mary B. Boyle ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Pregnant Rats ◽  
Abdominal Surface ◽  
Uterine Electrical Activity

Activity-dependent feedback modulation of spike patterning of supraoptic nucleus neurons by endogenous adenosine

2006 ◽  
Vol 291 (1) ◽  
pp. R83-R90 ◽  
Author(s):  
P. M. Bull ◽  
C. H. Brown ◽  
J. A. Russell ◽  
M. Ludwig
Keyword(s):  
Electrical Activity ◽  
Hazard Function ◽  
Supraoptic Nucleus ◽  
Neuronal Excitability ◽  
Cell Activity ◽  
Male Rats ◽  
Firing Rates ◽  
Endogenous Adenosine

Neuropeptide secretion from the dendrites of hypothalamic magnocellular supraoptic nucleus (SON) neurons contributes to the regulation of neuronal activity patterning, which ultimately determines their peptide output from axon terminals in the posterior pituitary gland. SON dendrites also secrete a number of other neuromodulators, including ATP. ATP degrades to adenosine in the extracellular space to complement transported adenosine acting on pre- and postsynaptic SON A1 receptors to reduce neuronal excitability, measured in vitro. To assess adenosine control of electrical activity in vivo, we made extracellular single-unit recordings of the electrical activity of SON neurons in anesthetized male rats. Microdialysis application (retrodialysis) of the A1 receptor antagonist, 8-cyclopentyl-1,3-dimethylxanthine (CPT) increased phasic vasopressin cell intraburst firing rates progressively over the first 5 s by 4.5 ± 1.6 Hz ( P < 0.05), and increased burst duration by 293 ± 64% ( P < 0.05). Hazard function plots were generated from interval interspike histograms and revealed that these effects were associated with increased postspike excitability. In contrast, CPT had no effect on the firing rates and hazard function plot profiles of continuously active vasopressin and oxytocin cells. However, CPT significantly increased clustering of spikes, as quantified by the index of dispersion, in oxytocin cells and continuously active vasopressin cells (by 267 ± 113% and 462 ± 67%, respectively, P < 0.05). Indeed, in 4 of 5 continuously active vasopressin cells, CPT induced a pseudophasic activity pattern. Together, these results indicate that endogenous adenosine is involved in the local control of SON cell activity in vivo.

Sign in / Sign up

Export Citation Format

Share Document