Effect of Substance P Injection into the Nucleus Tractus Solitarius of Rats on Cricothyroid and Thyroarytenoid Motor Activity and Cardiovascular and Respiratory Systems

2002 ◽  
Vol 111 (10) ◽  
pp. 875-883 ◽  
Author(s):  
Nancy M. Bauman ◽  
Erich S. Luschei ◽  
Deqiang Wang ◽  
William T. Talman

Identification of central neurotransmitters that mediate laryngeal adductor and/or tensor activity may prove useful in managing pathological laryngeal adduction as occurs in laryngospasm or apparent life-threatening events. The putative transmitter substance P (SP) is found in the nucleus tractus solitarius (NTS), in which laryngeal afferents terminate. Therefore, we studied the laryngeal, cardiovascular, and respiratory effects of SP injected into the NTS of rats. We completed bilateral stereotactic injections of 20 nL of SP (15 μmol) or control solution into the region of the NTS, the dorsal motor nucleus (DMN), or the nucleus gracilis (GR) in 30 anesthetized rats. Changes in diaphragm, cricothyroid (CT), and thyroarytenoid (TA) electromyography (EMG), as well as blood pressure (BP), were compared. The injection sites were verified histologically. Injection of SP into the NTS altered CT and/or TA EMG activity in all animals. The change ranged from complete inhibition, to a phasic increase, to a tonic increase. No change in laryngeal adductor EMG activity was seen in 8 of 9 animals after SP injections into the DMN (4/5) or GR (4/4), but 1 animal demonstrated brief inhibition of CT and TA EMG activity after SP injection into the DMN. Injection of SP into the NTS induced central apnea and a significant decrease in BP in all animals. The duration of apnea tended to be longer after NTS injections than after DMN or GR injections (p < .10 and p < .05, respectively). We conclude that stereotactic injections of putative neurotransmitters in rats may be accomplished to identify effects on laryngeal motor activity. Direct application of SP into the NTS consistently elicits a change in CT and/or TA EMG activity, ranging from inhibition to excitation. This model may prove useful in evaluating pharmacological targets of central reflex activity to manage life-threatening laryngeal reflex activity.

1980 ◽  
Vol 238 (1) ◽  
pp. R57-R64 ◽  
Author(s):  
J. Ciriello ◽  
F. R. Calaresu

Experiments were done in cats anesthetized with chloralose, paralyzed and artificially ventilated cats to obtain electrophysiological evidence on the medullary site of origin of vagal cardioinhibitory fibers. The regions of the nucleus ambiguus (AMB), dorsal motor nucleus of the vagus (DMV), nucleus tractus solitarius (NTS), and external cuneate nucleus (ECN) were systematically explored for units responding both to antidromic stimulation of the cardiac branches of the vagus (CBV) and to orthodromic stimulation of the carotid sinus and aortic depressor nerves. Eighty-six single units conforming to these criteria were found in the medulla: 30 in the AMB, 26 in the DMV, 12 in the NTS, 8 in the NTS-DMV border region, and 10 in the ECN. Antidromically evoked spikes had durations of 0.5--2.5 ms and followed stimulation frequencies of 20--500 Hz. The axons of these units conducted at velocities of 3.3--20.8 m/s. The specificity of activation of medullary units by cardioinhibitory fibers was tested in 11 units, which were found to respond consistently with an antidromic spike to stimulation of CBV but not to stimulation of the thoracic vagus. In eight spinal animals low threshold (less than 15 microA) sites eliciting vagal bradycardia were found in the same medullary nuclei where cardioinhibitory units had been located. These results indicate that vagal cardioinhibitory axons, originate in at least three medullary nuclei, the AMB, DMV, and NTS. Unit activity from the ECN may have been recorded from carioinhibitory fibers because of the short duration of the spike potentials.


1993 ◽  
Vol 335 (1) ◽  
pp. 109-122 ◽  
Author(s):  
Xu-Feng Huang ◽  
George Paxinos ◽  
Paul Halasz ◽  
Deborah McRitchie ◽  
Istvan Törk

2001 ◽  
Vol 281 (1) ◽  
pp. G164-G172 ◽  
Author(s):  
Mark W. Lewis ◽  
R. Alberto Travagli

Previous evidence suggests that substance P (SP) activates subpopulations of neurons within the dorsal motor nucleus of the vagus (DMV). In this study we aimed at identifying these subpopulations in relation to their gastrointestinal projection organs or vagal branches and characterizing pharmacologically the SP response. Using whole cell patch-clamp recordings from identified gastrointestinal-projecting vagal motoneurons, we found that SP induced an inward current in all neuronal groups except for cecum-projecting cells. The lowest percentage of SP-responding neurons was found in fundus-projecting cells, where SP also had a concentration-response curve that was shifted to the left ( P < 0.05). Independently from the projections, the SP response was reduced by sendide and MEN 10,376 and mimicked by a combination of [Sar9-Met(O2)11]SP and α-neurokinin. SP and α-neurokinin also increased the frequency, but not the amplitude, of postsynaptic currents. In conclusion, we demonstrated that SP induces both pre- and postsynaptic effects on DMV neurons via activation of neurokinin NK1 and NK2 receptors. The magnitude of the SP response was correlated to the peripheral target organ.


2001 ◽  
Vol 29 (02) ◽  
pp. 211-220 ◽  
Author(s):  
Chang Hyun Lee ◽  
Han Sol Jung ◽  
Tae Young Lee ◽  
Sang Ryoung Lee ◽  
Sang Won Yuk ◽  
...  

The purpose of this morphological study was to investigate the relation between the meridian, meridian points and viscera using neuroanatomical tracers. The common locations of the spinal cord and brain projecting to the stomach and Zusanli were observed following injection of CTB (cholera toxin B subunit) and pseudorabies viruses (PRV-Ba, Bartha strain and PRV-Ba-Gal, galactosidase insertion) into the stomach and Zusanli (ST36). After 4–5 days of survival following injection into twelve rats, they were perfused, and their spinal cords and brains were frozen sectioned (30 μm). These sections were stained by X-gal histochemical, CTB and PRV-Bia immunohistochemical staining methods, and examined with the light microscope. The results were as follows: Commonly labeled medulla oblongata regions were dorsal motor nucleus of vagus nerve (DMV), nucleus tractus solitarius (NTS) and area postrema (AP) following injection of CTB and PRV-Ba-Gal into stomach and Zusanli, respectively. In the spinal cord, commonly labeled neurons were found in thoracic, lumbar and sacral spinal segments. Densely labeled areas were found in lamina IV, V, VII (intermediolateral nucleus) and X of the spinal cord. In the brain, commonly labeled neurons were found in the A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular nucleus, dorsal motor nucleus of vagus nerve, nucleus tractus solitarius, area postrema, raphe obscurus nucleus, raphe pallidus nucleus, raphe magnus nucleus, gigantocellular nucleus, locus coeruleus, parabrachial nucleus, Kolliker-Fuse nucleus, A5 cell group, central gray matter, paraventricular hypothalamic nucleus, lateral hypothalamic nucleus, retrochiasmatic hypothalamic nucleus, bed nucleus of stria terminals and amygdaloid nucleus. Thus central autonomic center project both to the stomach and Zusanli. These morphological results suggest that there is a commonality of CNS cell groups in brain controlling stomach (viscera) and Zusanli (limb).


1991 ◽  
Vol 260 (1) ◽  
pp. G91-G96 ◽  
Author(s):  
R. L. White ◽  
C. D. Rossiter ◽  
P. J. Hornby ◽  
J. W. Harmon ◽  
D. K. Kasbekar ◽  
...  

The nucleus raphe obscurus (NRO) has recently emerged as an important nucleus for excitation of gastric motor activity through projections to the dorsal motor nucleus of the vagus (DMV) [P. J. Hornby, C. D. Rossiter, R. L. White, W. P. Norman, D. H. Kuhn, and R. A. Gillis. Am. J. Physiol. 258 (Gastrointest. Liver Physiol. 21): G91-G96, 1990; and M. J. McCann, G. E. Herman, and R. C. Rogers. Brain Res. 486: 181-184, 1989]. A neurotransmitter thought to be involved in this NRO-DMV pathway is thyrotropin-releasing hormone (TRH), a peptide that excites gastric activity when microinjected into the DMV. The purpose of the present study was to determine whether gastric acid and pepsin secretion were altered by 1) activation of neurons in the NRO by microinjection of kainic cid and 2) microinjection of TRH into the DMV in chloralose-anesthetized cats. Microinjection of kainic acid into the NRO increased gastric acid secretion [baseline was 6 +/- 2 (mu eq) H+/15 min (n = 7) and increased to 8 +/- 2, 26 +/- 11 (P less than 0.05), and 21 +/- 7 mu eq/15 min (P less than 0.05) during the first, second, and third 15-min periods after microinjection, respectively]. Pepsin output also increased from a baseline of 287 +/- 67 pepsin units (PU) (n = 4) to 507 +/- 126 PU 15 min postinjection, 541 +/- 118 PU 30 min after injection (P less than 0.05), 608 +/- 92 PU 45 min after injection (P less than 0.05), and 700 +/- 156 PU 60 min postinjection (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)


2009 ◽  
Vol 296 (1) ◽  
pp. G101-G111 ◽  
Author(s):  
Melissa A. Herman ◽  
Maureen T. Cruz ◽  
Niaz Sahibzada ◽  
Joseph Verbalis ◽  
Richard A. Gillis

It has been proposed that there is an “apparent monosynaptic” connection between gastric vagal afferent nerve terminals and inhibitory projection neurons in the nucleus tractus solitarius (NTS) and that two efferent parallel pathways from the dorsal motor nucleus of the vagus (DMV) influence peripheral organs associated with these reflexes ( 6 ). The purpose of our study was to verify the validity of these views as they relate to basal control of gastric motility. To test the validity of a direct connection of vagal afferent terminals (known to release l-glutamate) directly impacting second-order projection neurons, we evaluated the effect of GABAA receptor blockade in the area of the medial subnucleus of the tractus solitarius (mNTS) on gastric motility. Microinjection of bicuculline methiodide into the mNTS produced robust decreases in gastric motility (−1.6 ± 0.2 mmHg, P < 0.05, n = 23), which were prevented by cervical vagotomy and by pretreatment with kynurenic acid microinjected into the mNTS. Kynurenic acid per se had no effect on gastric motility. However, after GABAA receptor blockade in the mNTS, kynurenic acid produced a robust increase in gastric motility. To test for the contribution of two parallel efferent DMV pathways, we assessed the effect of either intravenous atropine methylbromide or NG-nitro-l-arginine methyl ester on baseline motility and on decreases in gastric motility induced by GABAA receptor blockade in the mNTS. Only atropine methylbromide altered baseline motility and prevented the effects of GABAA receptor blockade on gastric motility. Our data demonstrate the presence of intra-NTS GABAergic signaling between the vagal afferent nerve terminals and inhibitory projection neurons in the NTS and that the cholinergic-cholinergic excitatory pathway comprises the functionally relevant efferent arm of the vagovagal circuit.


1989 ◽  
Vol 23 (1-2) ◽  
pp. 149-153 ◽  
Author(s):  
Carlos R. Plata-Salaman ◽  
Atsuo Fukuda ◽  
Taketsugu Minami ◽  
Yutaka Oomura

1989 ◽  
Vol 257 (2) ◽  
pp. G266-G273
Author(s):  
K. Martin ◽  
T. H. Kong ◽  
W. Renehan ◽  
A. Schurr ◽  
W. Dong ◽  
...  

The central nervous system (CNS) regions regulating ileal water and ion absorption are unknown. We determined 1) the CNS origin of brain stem neurons that directly innervate the rat ileum, and 2) that these neurons influence intestinal water absorption. Horseradish peroxidase (HRP) was injected into the muscle layer of the rat ileum. The brains were examined for HRP reaction product (HRPRP) 3, 5, or 7 days later. Only cell bodies of the dorsal motor nucleus of the vagus (DMNV) were labeled. Unilateral cervical vagotomy prevented deposition in the ipsilateral DMNV. To determine whether the DMNV regulates ileal water absorption, electrical and chemical stimulation (30 microA, 4 Hz, 0.2 ms, and 300 pmol L-glutamate every 5 min, respectively) were used. Both the DMNV and the adjacent nucleus tractus solitarius (NTS) were stimulated, causing a reduction in water absorption. Bilateral vagotomy prevented the effect of bilateral electrical stimulation, but unilateral vagotomy did not prevent the decrease due to ipsilateral stimulation. These studies show that 1) the DMNV innervates the ileum, and 2) alteration of vagal efferent activity by stimulation of the DMNV and NTS reduces ileal water absorption.


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