Serotonergic innervation on the motoneurons in the mammalian brainstem

Takeuchi, Yoshihiro; Kojima, Munekado; Matsuura, Tadao; Sano, Yutaka

doi:10.1007/bf00315670

Cited by 75 publications

(34 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Involvement of 5-HT2 receptors in the 5-HT-induced depression of the XII discharge Serotonergic inputs to the XII motoneurons have been described (Takeuchi, Kojima, Matsuura & Sano, 1983) and 5-HT profiles detected throughout all the regions of the XII motor nucleus (Aldes, Marco & Chronister, 1989). These 5-HT inputs may originate from the medial reticular formation (Borke, Nau & Ringler, 1983), particularly the raphe nuclei which give rise to processes entering the XII motor nucleus (Aldes, Chronister, Marco, Haycock & Thibault, 1988).…”

Section: Serotonin and Hypoglossal Motoneuronsmentioning

confidence: 99%

Compared effects of serotonin on cervical and hypoglossal inspiratory activities: an in vitro study in the newborn rat.

Morin

Monteau

Hilaire

1992

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. Experiments were performed on the brain stem-spinal cord preparation of newborn rats, in which the phrenic and hypoglossal nerves continue to show rhythmic respiratory activity in vitro, in order to compare the effects of serotonin (5-HT) on both activities and to analyse the mechanisms responsible for the depression by 5-HT of the hypoglossal activity.2. Under control conditions, simultaneous recordings of the inspiratory discharges of hypoglossal and cervical roots showed that the two bursts did not start simultaneously and had different patterns (time-to-peak and peak values); this suggests that both pools of motoneurons did not share the same central drive(s).3. Adding 5-HT and related agents to the bathing medium delayed and depressed the hypoglossal inspiratory discharge via activation of 5-HT2 receptors since these effects were elicited by 5-HT2 agonists (a-methyl-5-HT and 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane-HCl (DOI)) but not by 5-HT1 agonists (RU 24969 and (± )-8-hydroxy-2-(di-N-propylamino)tetralin hydrobromide (8-OH-DPAT)). The 5-HT depression of the hypoglossal discharge was prevented by applying a pretreatment with a specific 5-HT2 antagonist (ketanserin). Parallel to the hypoglossal discharge decrease, 5-HT elicited a permanent cervical root discharge along with a persistent inspiratory bursting. Adding the 5-HT precursor L-tryptophan to the bathing medium depressed the hypoglossal (XII) discharge without affecting the cervical one.4. Local application of 5-HT within the hypoglossal motor nucleus decreased the hypoglossal output, revealing that the 5-HT depression of the hypoglossal discharge was at least partly mediated by the 5-HT effects at the level of the motoneurons. Local application of 5-HT within the cervical motor nucleus elicited a permanent firing in the cervical root with a persistent inspiratory bursting.5. Intracellular analysis confirmed the existence of differences in central respiratory drive between cervical and hypoglossal motoneurons under control conditions, as well as differences in response to 5-HT. All the hypoglossal motoneurons became silent under 5-HT bathing, and showed no change in the input membrane resistance, a moderate depolarization, and a delayed central respiratory MS 9503 D. MORIN, R. MONTEA U AND 0. HILAIRE drive with a decreased amplitude. The cervical motoneurons became more active during inspiration, despite a decrease in the amplitude of the central respiratory drive, which was compensated for by a large depolarization and an increased input membrane resistance. Some cervical motoneurons even fired at a low rate during expiration.6. Taken as a whole, these results suggest that the hypoglossal depression induced by 5-HT was due to the activation of 5-HT2 receptors located within the hypoglossal nucleus but the exact mechanisms whereby 5-HT modulates the hypoglossal outputs are still open to debate. The functional significance of the effects of 5-HT on hypoglossal inspiratory activity is discussed with reference to the obstructive apno...

show abstract

Section: Serotonin and Hypoglossal Motoneuronsmentioning

confidence: 99%

Compared effects of serotonin on cervical and hypoglossal inspiratory activities: an in vitro study in the newborn rat.

Morin

Monteau

Hilaire

1992

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Electron microscopically, 5-HT containing boutons have been investigated by (3H)-5-HT uptake (AGHAJANIAN and MCCALL, 1980) and by the PAP method (PELLETIER et al, 1981;PASIK et al, 1982;TAKEUCHI et al, 1983) in motor nuclei of various parts of the central nervous system in the mammal.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, these two reports are not consistent with each other in detail. On the other hand, 5-HT containing boutons have also been investigated by the uptake of (3H)-5-HT in the rat facial nucleus (AGHAJANIAN and MCCALL, 1980) and immunocytochemically in the brainstem of various mammals (PELLETIER et al, 1981;PASIK et al, 1982;TAKEUCHI et al, 1983). In spite of these reports, ultrastructural characteristics concerning the shape and size of dense cored vesicles in 5-HT containing boutons are still unclear.…”

mentioning

confidence: 99%

Substance P and 5-hydroxytryptamine immunoreactive presynaptic boutons on presumed .ALPHA.-motoneurons in the chicken ventral horn.

Atsumi

Sakamoto

Yokota

et al. 1985

Arch. Histol. Jap., Arch. Histol. Jpn

View full text Add to dashboard Cite

“…Neurons in the NA receive a high number of axosomatic serotonin (5HT) contacts, and the 5HT contacts surrounding neurons in the NA are among the most dense in the brainstem (Takeuchi et al, 1983). 5HT fibers also specifically surround CVNs which have been described as "ensheathed in 5HT immunoreactive axonal boutons" (Izzo et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

5HT2 receptor activation facilitates P2X receptor mediated excitatory neurotransmission to cardiac vagal neurons in the nucleus ambiguus

et al. 2008

View full text Add to dashboard Cite

SummaryParasympathetic preganglionic cardiac vagal neurons (CVNs) which dominate the control of heart rate are located within the nucleus ambiguus (NA). Serotonin (5HT), and in particular 5HT2 receptors, play an important role in cardiovascular function in the brainstem. However, there is a lack of information on the mechanisms of action of 5HT2 receptors in modulating parasympathetic cardiac activity. This study tests whether activation of 5HT2 receptors alters excitatory glutamatergic and purinergic neurotransmission to CVNs. Application of α-methyl-5-hydroxytryptamine (α-Me-5HT), a 5HT2 agonist, reversibly increased both the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs) in CVNs. Similar responses were obtained with alphamethyl-5-(2-thienylmethoxy)-1H-indole-3-ethanamine hydrochloride (BW723C86), and mchlorophenylpiperazine (m-CPP), 5HT2B and 5HT2B/C receptor agonists, respectively. The facilitation evoked by α-Me-5HT was prevented by the 5HT2B/C receptor antagonist SB206553 hydrochloride (SB206553). Interestingly, the blockage of both NMDA and non-NMDA glutamatergic receptors did not prevent α-Me-5HT-evoked facilitation of mEPSCs, however, the responses were blocked by the P2 receptor antagonist pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS). The responses evoked by α-Me-5HT were mimicked by application of α,β-methylene ATP (α,β-Me-ATP), a P2X receptor agonist, which were also blocked by PPADS. In summary, these results indicate activation of 5HT2 receptors facilitates excitatory purinergic, but not glutamatergic, neurotransmission to CVNs.

show abstract

Serotonergic innervation on the motoneurons in the mammalian brainstem

Cited by 75 publications

References 17 publications

Compared effects of serotonin on cervical and hypoglossal inspiratory activities: an in vitro study in the newborn rat.

Compared effects of serotonin on cervical and hypoglossal inspiratory activities: an in vitro study in the newborn rat.

Substance P and 5-hydroxytryptamine immunoreactive presynaptic boutons on presumed .ALPHA.-motoneurons in the chicken ventral horn.

5HT2 receptor activation facilitates P2X receptor mediated excitatory neurotransmission to cardiac vagal neurons in the nucleus ambiguus

Contact Info

Product

Resources

About