Nitric Oxide in the A5 Region Modulates Reaction of the Respiratory Center and Blood Pressure to Hypoxia in Rats

Pyatin, V. F.; Tatarnikov, V. S.

doi:10.1007/s10517-005-0236-z

Cited by 6 publications

(7 citation statements)

References 9 publications

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“…This suggestion is based on the data that multiceptive cells of A5 area regulate peripheral chemorefl ex and its sympathetic efferent pathway via activation of NO synthesis. Thus, hypoxia-induced respiratory and hypotensive response is more pronounced after blockage of NO synthesis in A5 area by microinjection of L-NAME comparing to this response before blockage [6]. Our experiments showed that NO can regulate respiratory activity via glutamate receptors in the rostral ventrolateral areas of the medulla oblongata (retrotrapezoid nucleus) in rats [5,9].…”

Section: Resultsmentioning

confidence: 57%

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NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats

Pyatin

Tatarnikov

2015

Bull Exp Biol Med

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In narcotized (40 mg/kg sodium ethaminal intraperitoneally) spontaneously breathing albino rats, experimental short-term hypoxia induced BP drop and increased phrenic nerve firing rate. Unilateral microinjection of a selective NMDA receptor blocker ketamine hydrochloride (50 nl; 4 mM) into A5 area did not affect BP and phrenic nerve fi ring rate. However, against the background of preliminary NMDA receptor blockage, hypoxia more markedly stimulated rhythmic activity of the respiratory center and hypotensive response. Unilateral microinjection of a selective blocker of non-NMDA receptors GAMS (50 nl; 4 mM) into A5 area did not change initial BP and phrenic nerve fi ring rate. The studied parameters in rats exposed to hypoxia after blockage of non-NMDA receptors in A5 area did not differ from the control levels. Thus, activity of the respiratory center and BP in rats during hypoxia is regulated by the structures in A5 area and NMDA glutamate receptors.

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Section: Resultsmentioning

confidence: 57%

“…Hypoxia leads to an increase in fi ring rate of the phrenic nerves (FRPN) and postganglionic sympathetic nerves and relaxation of arterial smooth muscles and BP drop via vascular NO-ergic mechanism [6]. Neuronal structures of A5 area are involved into the regulation of breathing and blood circulation during hypoxia in mammals [1,7,13].…”

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confidence: 99%

NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats

Pyatin

Tatarnikov

2015

Bull Exp Biol Med

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“…The latencies and durations of neuronal responses in the above zone and of corresponding changes in the mass activity recorded from the phrenic nerve under conditions of hypoxic stimulation practically coincided. This fact demonstrates that peripheral О 2 -sensitive chemoreceptors serve in this case as sources of the afferent influences [1,7]. An increase in the frequency of bursts in the phrenic nerve (by 73.8 ± 1.9%, on average; Р < 0.05) and increase in the amplitude of bursts (by 20.1 ± 0.5%; Р < 0.05) corresponded to hypoxia-related activation of A5 neurons (Fig.…”

Section: Resultsmentioning

confidence: 62%

“…Finally, respiration-related modulation of tonic electrical activity of noradrenergic neurons of zone A5 and intensification of such activity in hypoxia [1] are indicative of a possibility that these neurons interact with neurons of the respiratory center. An inhibitory tonic influence of neurons of zone A5 on the activity of neurons of the respiratory center [5][6][7] shows that, probably, cells of the corresponding brainstem nuclei are interconnected with reciprocal synaptic linkages. All the above-mentioned data agree with the concept that the activity of noradrenergic A5 neurons, which exert modulatory effects on the respiratory and sympathetic chemoreflexes [7,8], can, to a considerable extent, be determined by convergence of afferent signals of a different nature on the cells of the above zone.…”

Section: Introductionmentioning

confidence: 99%

Activation of neurons of zone A5 of the rat brain upon hypoxic and thermonociceptive stimulation and switching off of the central respiratory generator

2006

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We recorded spike activity of noradrenergic neurons of zone A5 (n = 89) in the brain of anesthetized rats under conditions of hypoxic stimulation (breathing with pure N 2 , 10 sec), thermonociceptive stimulation (tail-flick test), and reversible hypothermal blocking of the central respiratory activity. Hypoxic stimulation of peripheral О 2 -sensitive chemoreceptors considerably increased the discharge frequency in all the examined neurons and induced tachypnea and a hypotensive reaction. Sixty-nine (77.5%) neurons of the studied group were tested using nociceptive stimulation (thermal stimulation of the tail); such stimulation resulted in a multifold increase in their discharge frequency. This was accompanied by tachypnea and a hypertensive response. Thus, we first demonstrated the role of nociception in the control of activity of noradrenergic neurons in zone A5 and the role of nociceptive afferent signals in the modulation of functions of the respiratory and cardiovascular systems mediated by neurons of the above zone. Under conditions of blocking of the central respiratory activity, we examined 36 (40.4%) neurons of zone A5 and first observed the effect of strong activation of a significant proportion of these cells upon switching off of respiration. This fact shows that there is an activating "respiratory" drive on neurons of zone A5 (probably, from the side of an expiratory neuronal population of the respiratory center) and allows us to hypothesize on the genesis of "respiratory" modulation of these cells. The activity of 16 (18.0%) cells was recorded under conditions of consecutive applications of the above stimuli; all the neurons were activated by the respective afferent influences. The simultaneously induced effects of hypoxic and nociceptive stimulations on the activity of neurons of zone A5 were additive. Thus, we first obtained proofs in favor of the multimodality of noradrenergic neurons of the above zone. This feature is a significant factor providing integrative interaction between the respiratory and cardiovascular systems and the system of nociception.

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“…This hypothesis is based on the fact that pontine multireceptive A5 neurons regulate peripheral chemoreflex via stimulation of NO synthesis. In particular, after blockade of NO-synthase by microinjection of L-NAME into A5 region in rats, hypoxia produces more pronounced respiratory and hypotensive reactions in comparison with those evoked before the blockade [3]. Thus, NMDA GR are involved in the synaptic mechanism of the regulation of SBP and respiration during thermal nociceptive stimulation.…”

Section: Resultsmentioning

confidence: 97%

Role of NMDA- and non-NMDA Subtypes of Glutamate Receptors in A5 Neuronal Structures in the Regulation of Respiration and Circulation during Thermal Nociceptive Stimulation in Rats

2008

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In narcotized albino rats, thermal nociceptive stimulation elevated systemic blood pressure and increased the frequency of respiratory rhythm generation. Unilateral microinjection of ketamine hydrochloride, a selective blocker for NMDA receptors, into A5 region did not change the baseline parameters of multineuronal activity in the phrenic nerve and systemic blood pressure. Under conditions of NMDA-receptor blockade, thermal nociceptive stimulation evoked more pronounced respiratory response (in comparison to that observed before ketamine treatment), but induced smaller blood pressure rise. Unilateral microinjection of GAMS, a selective blocker for non-NMDA receptors, into A5 region did not modify the examined baseline parameters and the nociceptive response. It is concluded that during thermal nociceptive stimulation, activity of the respiratory center and blood pressure in rats are controlled by neuronal structures in A5 region via NMDA subtype of glutamate receptors.

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Nitric Oxide in the A5 Region Modulates Reaction of the Respiratory Center and Blood Pressure to Hypoxia in Rats

Cited by 6 publications

References 9 publications

NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats

NMDA Receptors of A5 Area in the Regulation of Blood Pressure and Respiratory Activity during Hypoxia in Rats

Activation of neurons of zone A5 of the rat brain upon hypoxic and thermonociceptive stimulation and switching off of the central respiratory generator

Role of NMDA- and non-NMDA Subtypes of Glutamate Receptors in A5 Neuronal Structures in the Regulation of Respiration and Circulation during Thermal Nociceptive Stimulation in Rats

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