Effect of sublingual nitrate on respiratory reflexes arising from stimulation of juxta-pulmonary capillary (J) receptors by i.v. lobeline and short duration exercise

2012 ◽  
Vol 181 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Ashima Anand ◽  
Niraj Srivastava ◽  
Hans Raj
1989 ◽  
Vol 62 (6) ◽  
pp. 1225-1236 ◽  
Author(s):  
S. M. Gurahian ◽  
S. H. Chandler ◽  
L. J. Goldberg

1. The effects of repetitive stimulation of the nucleus pontis caudalis and nucleus gigantocellularis (PnC-Gi) of the reticular formation on jaw opener and closer motoneurons were examined. The PnC-Gi was stimulated at 75 Hz at current intensities less than 90 microA. 2. Rhythmically occurring, long-duration, depolarizing membrane potentials in jaw opener motoneurons [excitatory masticatory drive potential (E-MDP)] and long-duration hyperpolarizing membrane potentials [inhibitory masticatory drive potentials (I-MDP)] in jaw closer motoneurons were evoked by 40-Hz repetitive masticatory cortex stimulation. These potentials were completely suppressed by PnC-Gi stimulation. PnC-Gi stimulation also suppressed the short-duration, stimulus-locked depolarizations [excitatory postsynaptic potentials (EPSPs)] in jaw opener motoneurons and short-duration, stimulus-locked hyperpolarizations [inhibitory postsynaptic potentials (IPSPs)] in jaw closer motoneurons, evoked by the same repetitive cortical stimulation. 3. Short pulse train (3 pulses; 500 Hz) stimulation of the masticatory area of the cortex in the absence of rhythmical jaw movements activated the short-latency paucisynaptic corticotrigeminal pathways and evoked short-duration EPSPs and IPSPs in jaw opener and closer motoneurons, respectively. The same PnC-Gi stimulation that completely suppressed rhythmical MDPs, and stimulus-locked PSPs evoked by repetitive stimulation to the masticatory area of the cortex, produced an average reduction in PSP amplitude of 22 and 17% in jaw closer and opener motoneurons, respectively. 4. PnC-Gi stimulation produced minimal effects on the amplitude of the antidromic digastric field potential or on the intracellularly recorded antidromic digastric action potential. Moreover, PnC-Gi stimulation had little effect on jaw opener or jaw closer motoneuron membrane resting potentials in the absence of rhythmical jaw movements (RJMs). PnC-Gi stimulation produced variable effects on conductance pulses elicited in jaw opener and closer motoneurons in the absence of RJMs. 5. These results indicate that the powerful suppression of cortically evoked MDPs in opener and closer motoneurons during PnC-Gi stimulation is most likely not a result of postsynaptic inhibition of trigeminal motoneurons. It is proposed that this suppression is a result of suppression of activity in neurons responsible for masticatory rhythm generation.


1959 ◽  
Vol 196 (2) ◽  
pp. 327-329 ◽  
Author(s):  
Raymond R. Walsh

A single, short-duration electrical stimulus delivered to one olfactory bulb evokes a potential in the contralateral bulb. As recorded with a unipolar electrode, the potential is negative central to, and positive peripheral to the external plexiform layer. Bipolar recordings from multiple sites show that the potential is not actively propagated. The potential summates in response to tetanic stimulation and is blocked by anoxia and dimethyl ether d-tubocurarine. In addition to confirming the existence of an interolfactory bulb system, the electrophysiological evidence in conjunction with known anatomical relationships strongly suggests that the evoked potential is a postsynaptic potential of the internal granular cells.


1991 ◽  
Vol 70 (6) ◽  
pp. 2539-2550 ◽  
Author(s):  
F. A. Hopp ◽  
J. L. Seagard ◽  
J. Bajic ◽  
E. J. Zuperku

Respiratory responses arising from both chemical stimulation of vascularly isolated aortic body (AB) and carotid body (CB) chemoreceptors and electrical stimulation of aortic nerve (AN) and carotid sinus nerve (CSN) afferents were compared in the anesthetized dog. Respiratory reflexes were measured as changes in inspiratory duration (TI), expiratory duration (TE), and peak averaged phrenic nerve activity (PPNG). Tonic AN and AB stimulations shortened TI and TE with no change in PPNG, while tonic CSN and CB stimulations shortened TE, increased PPNG, and transiently lengthened TI. Phasic AB and AN stimulations throughout inspiration shortened TI with no changes in PPNG or the following TE; however, similar phasic stimulations of the CB and CSN increased both TI and PPNG and decreased the following TE. Phasic AN stimulation during expiration decreased TE and the following TI with no change in PPNG. Similar stimulations of the CB and CSN decreased TE; however, the following TI and PPNG were increased. These findings differ from those found in the cat and suggest that aortic chemoreceptors affect mainly phase timing, while carotid chemoreceptors affect both timing and respiratory drive.


1998 ◽  
Vol 80 (6) ◽  
pp. 3373-3379 ◽  
Author(s):  
A. K. Moschovakis ◽  
Y. Dalezios ◽  
J. Petit ◽  
A. A. Grantyn

Moschovakis, A. K., Y. Dalezios, J. Petit, and A. A. Grantyn. New mechanism that accounts for position sensitivity of saccades evoked in response to stimulation of superior colliculus. J. Neurophysiol. 80: 3373–3379, 1998. Electrical stimulation of the feline superior colliculus (SC) is known to evoke saccades whose size depends on the site stimulated (the “characteristic vector” of evoked saccades) and the initial position of the eyes. Similar stimuli were recently shown to produce slow drifts that are presumably caused by relatively direct projections of the SC onto extraocular motoneurons. Both slow and fast evoked eye movements are similarly affected by the initial position of the eyes, despite their dissimilar metrics, kinematics, and anatomic substrates. We tested the hypothesis that the position sensitivity of evoked saccades is due to the superposition of largely position-invariant saccades and position-dependent slow drifts. We show that such a mechanism can account for the fact that the position sensitivity of evoked saccades increases together with the size of their characteristic vector. Consistent with it, the position sensitivity of saccades drops considerably when the contribution of slow drifts is minimal as, for example, when there is no overlap between evoked saccades and short-duration trains of high-frequency stimuli.


1999 ◽  
Vol 81 (3) ◽  
pp. 1150-1161 ◽  
Author(s):  
Irene C. Solomon ◽  
Norman H. Edelman ◽  
Judith A. Neubauer

Patterns of phrenic motor output evoked by chemical stimulation of neurons located in the pre-Bötzinger complex in vivo. The pre-Bötzinger complex (pre-BötC) has been proposed to be essential for respiratory rhythm generation from work in vitro. Much less, however, is known about its role in the generation and modulation of respiratory rhythm in vivo. Therefore we examined whether chemical stimulation of the in vivo pre-BötC manifests respiratory modulation consistent with a respiratory rhythm generator. In chloralose- or chloralose/urethan-anesthetized, vagotomized cats, we recorded phrenic nerve discharge and arterial blood pressure in response to chemical stimulation of neurons located in the pre-BötC with dl-homocysteic acid (DLH; 10 mM; 21 nl). In 115 of the 122 sites examined in the pre-BötC, unilateral microinjection of DLH produced an increase in phrenic nerve discharge that was characterized by one of the following changes in cycle timing and pattern: 1) a rapid series of high-amplitude, rapid rate of rise, short-duration bursts, 2) tonic excitation (with or without respiratory oscillations), 3) an integration of the first two types of responses (i.e., tonic excitation with high-amplitude, short-duration bursts superimposed), or 4) augmented bursts in the phrenic neurogram (i.e., eupneic breath ending with a high-amplitude, short-duration burst). In 107 of these sites, the phrenic neurogram response was accompanied by an increase or decrease (≥10 mmHg) in arterial blood pressure. Thus increases in respiratory burst frequency and production of tonic discharge of inspiratory output, both of which have been seen in vitro, as well as modulation of burst pattern can be produced by local perturbations of excitatory amino acid neurotransmission in the pre-BötC in vivo. These findings are consistent with the proposed role of this region as the locus for respiratory rhythm generation.


2008 ◽  
Vol 53 (22) ◽  
pp. 6639
Author(s):  
D E Kruse ◽  
M A Mackanos ◽  
C E O'Connell-Rodwell ◽  
C H Contag ◽  
K W Ferrara

1973 ◽  
Vol 44 (6) ◽  
pp. 519-538 ◽  
Author(s):  
S. K. Jain ◽  
Diana Trenchard ◽  
Felicity Reynolds ◽  
M. I. M. Noble ◽  
A. Guz

1. The effect of breathing anaesthetic aerosols (lignocaine 20% and bupivacaine 5%) on respiratory reflexes was studied in rabbits. 2. The cough reflex was blocked in every experiment. 3. The inflation reflex was abolished in eleven out of twenty-six rabbits given lignocaine aerosol and in fourteen out of fifteen rabbits given bupivacaine aerosol. 4. The deflation reflex was blocked pari passu with the inflation reflex. 5. The ventilatory response to histamine was sometimes blocked; more commonly it was partially preserved. 6. The ventilatory response to phenyldiguanide was never impaired and often enhanced. 7. Bronchoconstriction produced by electrical stimulation of the peripheral cut ends of the cervical vagus nerves was unaffected. 8. Block of the above respiratory reflexes was associated with slower, deeper breathing. 9. Bupivacaine has produced more consistent and reliable results than lignocaine; the effects were reversible in both cases usually within 30 min. 10. Plasma concentrations of both anaesthetics were usually below the generally accepted toxic concentrations in man. 11. Control experiments using intravenous infusions of the anaesthetics proved that none of the effects could have been produced by systemic effects of the absorbed anaesthetic. 12. No pathological changes were found in the airways on both macroscopic and microscopic examination. 13. The experiments show that it is possible to block respiratory reflexes whose afferents arise from the airways, and to preserve a reflex arising at alveolar level.


1975 ◽  
Vol 38 (6) ◽  
pp. 1045-1050 ◽  
Author(s):  
D. S. Dain ◽  
H. A. Boushey ◽  
W. M. Gold

The effects of inhalation of 100 breaths of bupivacaine hydrochloride (5 percent solution in saline) on the cough reflex, the Breuer-Hering inflation, reflex, and the duration of apnea and bronchoconstriction produced by histamine aerosol were studied in nine anesthetized dogs. Cough was abolished in every animal; the duration of the inflation reflex was shortened from 47 +/- 4.6 s (mean plus or minus SE) to 16 +/- 3.4 s. The duration apnea produced by histamine was abolished or shortened and the rise in resistance was diminished from 170 plus or minus 22 per cent (control) to 49 +/- 6 per cent (after bupivacaine). These reflexes returned toward control values within 45 min. Bupivacaine inhibited the bronchoconstriction produced by electrical stimulation of the distal ends of cut vagus nerves both in dogs and in rabbits, but it did not alter the rise in resistance produced by histamine aerosol in vagotomized dogs. We conclude that administration of bupivacaine aerosol produces a reversible blockage of both afferent and efferent nervous activity in airways without abolishing the ability of smooth muscles to contract.


1991 ◽  
Vol 261 (6) ◽  
pp. L443-L448 ◽  
Author(s):  
D. R. Karius ◽  
L. M. Ling ◽  
D. F. Speck

Previous studies have indicated that excitatory amino acids are involved in many afferent pathways. This study investigated the effects of intravenous MK-801 [an N-methyl-D-aspartate (NMDA) receptor-associated channel blocker] on several well-known respiratory reflexes elicited by afferent stimulation of the superior laryngeal (SLN), the intercostal (ICN), and the phrenic (PN) nerves. Control responses to stimulation were obtained from recordings of phrenic nerve activity in decerebrate, paralyzed cats. Inspiratory termination elicited by the delivery of stimulus trains to either the SLN or the ICN persisted after MK-801. The onset latency or duration of the short-latency excitations produced by SLN or ICN stimulation were unchanged. The transient inhibitions produced by SLN, ICN, PN, or medullary stimulation showed no significant changes in threshold, onset latency, or duration. Withholding lung inflation produced apneusis after administration of MK-801, indicating a central effect of the drug. Higher doses of MK-801 did not alter the parameters of these reflexes. These data indicate that NMDA-dependent neurotransmission is not required for the production of these reflexes.


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