Oxytocin predominantly excites putative oxytocin neurons in the rat supraoptic nucleus in vitro

Yamashita, Hiroshi; Okuya, Shigeru; Inenaga, Kiyotoshi; Kasai, Masanori; Uesugi, Sayuri; Kannan, Hiroshi; Kaneko, Toshio

doi:10.1016/0006-8993(87)90920-6

Cited by 111 publications

(58 citation statements)

References 18 publications

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“…Meanwhile, there was a relatively large increase in membrane potential (E m ) depolarization (P Ͻ 0.01). This result is in agreement with previous work (Yamashita et al 1987).…”

Section: Excitatory Effects Of Ot Via Pg Synthesissupporting

confidence: 94%

“…Although PGs have excitatory effects on both OT and vasopressin (VP) neurons (Ibrahim et al 1999), increased blood OT concentrations (Knigge et al 2003), and DAG and membrane arachidonic acid (AA) could be converted to PGs, it has not been established that PGs are mediators of OT's actions, especially excitation, in SON neurons. Furthermore, type 1 VP receptors on both OT and VP neurons also belong to G␣ q/11 /GPCRs , and VP neurons can be activated by OT (Yamashita et al 1987). If OT's effects on intracellular signals and neuronal excitability represent common responses to G␣ q/11 /GPCR activation, then similar effects of OT should be observed in both OT and VP neurons.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms Underlying Oxytocin-Induced Excitation of Supraoptic Neurons: Prostaglandin Mediation of Actin Polymerization

Wang

Hatton

2006

Journal of Neurophysiology

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Wang, Yu-Feng and Glenn I. Hatton. Mechanisms underlying oxytocin-induced excitation of supraoptic neurons: prostaglandin mediation of actin polymerization. J Neurophysiol 95: 3933-3947, 2006. First published March 22, 2006 doi:10.1152/jn.01267.2005. In nonneuronal tissues, activation of oxytocin receptors (OTRs), like other G␣ q/11 type G-protein-coupled receptors (G␣ q/11 /GPCRs), increase prostaglandin (PG) expression. This is not known for the OTRs expressed by central OT neurons. We examined mechanisms underlying OT's effects on supraoptic nucleus (SON) OT and vasopressin (VP) neurons in hypothalamic slices from lactating rats. OT application (10 pM, 10 min) significantly increased firing rates of OT and VP neurons, both of which expressed OTRs. Indomethacin, an inhibitor of PG synthetases, blocked these increases. OTR (but not a V 1 receptor) antagonist blocked OT effects without blocking the excitatory effect of PGE 2 . Tetanus toxin blocked OT effects on fast synaptic inputs and firing activity of SON neurons but not OT-evoked depolarization, suggesting involvement of both pre-and postsynaptic neurons. Indomethacin also blocked the excitatory effects of phenylephrine, another G␣ q/11 /GPCR activating agent but not those of PGE 2 , a non-G␣ q/11 / GPCR activating agent in the SON. OT or phenylephrine, but not glutamate or KCl, enhanced cyclooxygenase 2 expression at cytosolic loci in SON neurons and nearby astrocytes, as revealed by immunocytochemistry. This OT effect was not blocked by TTX. Western blot analyses showed that OT significantly increased cyclooxygenase 2 but not actin expression. OT promoted the formation of filamentous actin (F-actin) networks at membrane subcortical areas of both OT and VP neurons. Indomethacin blocked enhancement of F-actin networks by OT but not by PGE 2 . These results indicate that PGs serve as a common mediator of G␣ q/11 /GPCR-activating agents in neuronal function.

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“…Meanwhile, there was a relatively large increase in membrane potential (E m ) depolarization (P Ͻ 0.01). This result is in agreement with previous work (Yamashita et al 1987).…”

Section: Excitatory Effects Of Ot Via Pg Synthesissupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Mechanisms Underlying Oxytocin-Induced Excitation of Supraoptic Neurons: Prostaglandin Mediation of Actin Polymerization

Wang

Hatton

2006

Journal of Neurophysiology

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“…In these regions, the peptide would exacerbate unacceptable thoughts resulting in frequent and intrusive preoccupations as well as sexual and aggressive impulses. Given the positive feedback properties of this system under certain physiological conditions, 79 OT could sensitize the system leading to its own increased release. The discomfort associated with these concerns (obsessions) and the increased levels of central OT would result, at least in part, in accomplishment of compulsory rituals, such as grooming and compulsions of verification.…”

Section: Discussionmentioning

confidence: 99%

Neuroanatomical and cellular substrates of hypergrooming induced by microinjection of oxytocin in central nucleus of amygdala, an experimental model of compulsive behavior

et al. 2007

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Oxytocin (OT) is a neurosecretory nonapeptide synthesized in hypothalamic cells that project to the neurohypophysis as well as to widely distributed sites in the central nervous system. Central OT microinjections induce a variety of cognitive, sexual, reproductive, grooming and affiliative behaviors in animals. Obsessive-compulsive disorder (OCD) includes a range of cognitive and behavioral symptoms that bear some relationship with OT. Here, we study the neuroanatomical and cellular substrates of the hypergrooming induced by administration of OT in the central nucleus of amygdala (CeA). In this context, this hypergrooming is considered as a model of compulsive behavior. Our data suggest a link between the CeA and the hypothalamic grooming area (HGA). The HGA includes parts of the paraventricular nucleus and the dorsal hypothalamic area. Our data on colocalization of OT (immunohistochemistry for peptide), OT receptor (binding assay) and its retrogradely labeled cells after Fluoro-Gold injection in the CeA suggest that CeA and connections are important substrates of the circuit underlying this OT-dependent compulsive behavioral pattern.

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“…Once released, OT could exert a direct modulatory action on O T neuron excitability (10). and recent studies employing microinjections of OT into individual SO and PV nuclei of suckled rats, have suggested that this locally released OT may modulate the pattern of milk ejection responses ( I I).…”

Section: (4)mentioning

confidence: 99%

Oxytocin in the Bed Nucleus of the Stria Terminalis and Lateral Septum Facilitates Bursting of Hypothalamic Oxytocin Neurons in Suckled Rats

Moos

Ingram

Wakerley

et al. 1991

J Neuroendocrinology

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Several regions of the forebrain possess high densities of oxytocin (0T)-binding sites including the bed nucleus of the stria terminalis (BST) and lateral septum (LS). In order to examine whether these regions participate in the central facilitation of the milk ejection reflex by OT, microinjections of OT (1 ng in 100 nl containing Janus Green dye) were made into the BST (13 tests) or LS (9 tests) of anaesthetized, suckled rats, while recording the electrical activity of OT neurons in the contralateral supraoptic nucleus. Histological localization of injection sites using Janus Green demonstrated that all BST injections were close to t h e anterior commissure, and LS injections were all located in the ventral division of the LS. Film autoradiographic visualization of OT-binding sites (in 7 tests using [1251]OT antagonist) confirmed that the BST and LS injections were located within regions of high OT binding. Injections into both regions facilitated the milk ejection reflex by increasing either the frequency and/or amplitude of OT neuron bursts, or by triggering bursts in animals that previously had shown no milk ejection responses; the mean number of milk ejections in the 30 rnin before and after injection increasing from 1.6+0.5 to 3.650.5 for BST and from 1.5f0.6 to 3.9f0.4 for LS. The OT microinjections had a more variable effect on background activity of OT neurons, increasing firing in s o m e c a s e s and not in others. This facilitatory effect was similar to that induced by microinjections into the lateral ventricle, but w a s smaller and delayed compared to that induced by injection into the third ventricle (9 tests), possibly due to unilateral activation of target sites. The facilitatory effect was unlikely to have been due to diffusion of OT into the ventricle, since injections into control sites (striatum and thalamus) at similar distances from the ventricle (9 tests) had no facilitatory effect (number of bursts during 30 rnin before and after injection; 2.2k0.5 and 1.8+0.5, respectively). These data suggest that limbic structures (BST a n d LS) participate in the action of central OT on the pattern of milk ejections in the suckled rat.In lactating rats, oxytocin (OT) neurons in the paraventricular (PV) and supraoptic (SO) nuclei of the hypothalamus display periodic and coordinated bursting activity during suckling, resulting in the pulsatile release of O T from the neurohypophysis and consequent milk ejection (1,2). The periodicity and amplitude of this bursting activity is centrally facilitated by O T itself, since intracerebroventricular (icv) injections of OT dramatically enhance their frequency and the number of action potentials in each burst (3--5). Furthermore, the ability of OT antagonists to suppress bursting activity (4) indicates that endogenous OT plays an important role in regulating the normal pattern of milk ejection responses. Results from injections into different parts of the ventricular system, suggest that the target site(s) for this OT facilitation resides within perive...

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Oxytocin predominantly excites putative oxytocin neurons in the rat supraoptic nucleus in vitro

Cited by 111 publications

References 18 publications

Mechanisms Underlying Oxytocin-Induced Excitation of Supraoptic Neurons: Prostaglandin Mediation of Actin Polymerization

Mechanisms Underlying Oxytocin-Induced Excitation of Supraoptic Neurons: Prostaglandin Mediation of Actin Polymerization

Neuroanatomical and cellular substrates of hypergrooming induced by microinjection of oxytocin in central nucleus of amygdala, an experimental model of compulsive behavior

Oxytocin in the Bed Nucleus of the Stria Terminalis and Lateral Septum Facilitates Bursting of Hypothalamic Oxytocin Neurons in Suckled Rats

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