Somatostatin selectively ablates post-inspiratory activity after injection into the Bötzinger complex

Burke, Peter G R; Abbott, Stephen B.G.; McMullan, Simon; Goodchild, Ann K.; Pilowsky, Paul M.

doi:10.1016/j.neuroscience.2010.01.065

Cited by 52 publications

(57 citation statements)

References 58 publications

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“…The left cervical nerve was dissected proximal to the carotid bifurcation, tied with 6-0 silk thread and cut. The left splanchnic, renal, and lumbar sympathetic nerves were approached via a retroperitoneal incision, as described previously (5,6). Dorsal roots were exposed by an L1-L4 laminectomy and removal of the dura.…”

Section: Electrophysiological Experimentsmentioning

confidence: 99%

Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons

Burke

Neale

Korim

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

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To determine the organization of presympathetic vasomotor drive by phenotypic populations of rostral ventrolateral medulla (RVLM) neurons, we examined the somatosympathetic reflex (SSR) evoked in four sympathetic nerves together with selective lesions of RVLM presympathetic neurons. Urethane-anesthetized (1.3 g/kg ip), paralyzed, vagotomized and artificially ventilated Sprague-Dawley rats (n = 41) were used. First, we determined the afferent inputs activated by sciatic nerve (SN) stimulation at graded stimulus intensities (50 sweeps at 0.5-1 Hz, 1-80 V). Second, we recorded sympathetic nerve responses (cervical, renal, splanchnic, and lumbar) to intensities of SN stimulation that activated A-fiber afferents (low) or both A- and C-fiber afferents (high). Third, with low-intensity SN stimulation, we examined the cervical SSR following RVLM microinjection of somatostatin, and we determined the splanchnic SSR in rats in which presympathetic C1 neurons were lesioned following intraspinal injections of anti-dopamine-β-hydroxylase-saporin (anti-DβH-SAP). Low-intensity SN stimulation activated A-fiber afferents and evoked biphasic responses in the renal, splanchnic, and lumbar nerves and a single peak in the cervical nerve. Depletion of presympathetic C1 neurons (59 ± 4% tyrosine hydroxylase immunoreactivity profiles lesioned) eliminated peak 2 of the splanchnic SSR and attenuated peak 1, suggesting that only RVLM neurons with fast axonal conduction were spared. RVLM injections of somatostatin abolished the single early peak of cervical SSR confirming that RVLM neurons with fast axonal conduction were inhibited by somatostatin. It is concluded that unmyelinated RVLM presympathetic neurons, presumed to be all C1, innervate splanchnic, renal, and lumbar but not cervical sympathetic outflows, whereas myelinated C1 and non-C1 RVLM neurons innervate all sympathetic outflows examined. These findings suggest that multiple levels of neural control of vasomotor tone exist; myelinated populations may set baseline tone, while unmyelinated neurons may be recruited to provide actions at specific vascular beds in response to distinct stressors.

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Section: Electrophysiological Experimentsmentioning

confidence: 99%

Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons

Burke

Neale

Korim

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

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“…It is, therefore, reasonable for the preBötzinger complex and the other premotoneurons and motoneurons in the VRC to receive so much attention. The role of these neurons is dealt with extensively elsewhere (Boers et al, 2005;Burke et al, 2010;Feldman and McCrimmon, 1986;Monnier et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Peptides, Serotonin, and Breathing

Pilowsky

2014

Progress in Brain Research

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“…Bombesin, and its three receptors (28,46), are all present in the spinal cord of rat and other species, in particular, within the dorsal horn (71) and the autonomic nuclei (10). The effect of activating and inhibiting bombesin receptors in the thoracic spinal cord, on sympathetic nerve activity, phrenic nerve discharge, and adaptive reflexes remains unknown.There is a growing body of evidence that different peptides, such as somatostatin, pituitary adenylate cyclase-activating polypeptide (PACAP), galanin, and orexin A, act as neurotransmitters/neuromodulators in the cardiorespiratory system (1,7,18,63,65). These peptides differentially affect sympathetic tone and adaptive reflexes.…”

mentioning

confidence: 99%

“…There is a growing body of evidence that different peptides, such as somatostatin, pituitary adenylate cyclase-activating polypeptide (PACAP), galanin, and orexin A, act as neurotransmitters/neuromodulators in the cardiorespiratory system (1,7,18,63,65). These peptides differentially affect sympathetic tone and adaptive reflexes.…”

mentioning

confidence: 99%

Intrathecal bombesin is sympathoexcitatory and pressor in rat

Zogovic

Pilowsky

2011

American Journal of Physiology-Regulatory, Integrative and Comp

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Zogovic B, Pilowsky PM. Intrathecal bombesin is sympathoexcitatory and pressor in rat. Am J Physiol Regul Integr Comp Physiol 301: R1486 -R1494, 2011. First published August 17, 2011 doi:10.1152/ajpregu.00297.2011.-Bombesin, a 14 aminoacid peptide, is pressor when administered intravenously in rat and pressor and sympathoexcitatory when applied intracerebroventricularly. To determine the spinal effects of bombesin, the peptide was administered acutely in the intrathecal space at around thoracic spinal cord level six of urethane-anesthetized, paralyzed, and bilaterally vagotomized rats. Blood pressure, heart rate, splanchnic sympathetic nerve activity (sSNA), phrenic nerve activity, and end-tidal CO 2 were monitored to evaluate changes in the cardiorespiratory systems. Bombesin elicited a long-lasting excitation of sSNA associated with an increase in blood pressure and tachycardia. There was a mean increase in arterial blood pressure of 52 Ϯ 5 mmHg (300 M; P Ͻ 0.01). Heart rate and sSNA also increased by 40 Ϯ 4 beats/min (P Ͻ 0.01) and 162 Ϯ 33% (P Ͻ 0.01), respectively. Phrenic nerve amplitude (PNamp, 73 Ϯ 8%, P Ͻ 0.01) and phrenic expiratory period (ϩ0.16 Ϯ 0.02 s, P Ͻ 0.05) increased following 300 M bombesin. The gain of the sympathetic baroreflex increased from Ϫ2.8 Ϯ 0.7 to Ϫ5.4 Ϯ 0.9% (P Ͻ 0.01), whereas the sSNA range was increased by 99 Ϯ 26% (P Ͻ 0.01). During hyperoxic hypercapnia (10% CO2 in O2, 90 s), bombesin potentiated the responses in heart rate (Ϫ25 Ϯ 5 beats/min, P Ͻ 0.01) and sSNA (ϩ136 Ϯ 29%, P Ͻ 0.001) but reduced PNamp (from 58 Ϯ 6 to 39 Ϯ 7%, P Ͻ 0.05). Finally, ICI-216,140 (1 mM), an in vivo antagonist for the bombesin receptor 2, attenuated the effects of 300 M bombesin on blood pressure (21 Ϯ 7 mmHg, P Ͻ 0.01). We conclude that bombesin is sympathoexcitatory at thoracic spinal segments. The effect on phrenic nerve activity may the result of spinobulbar pathways and activation of local motoneuronal pools. blood pressure; heart rate; splanchnic sympathetic nerve activity; phrenic nerve activity; baroreflex SYMPATHETIC PREGANGLIONIC neurons (SPN) located in the intermediolateral cell columns of the spinal cord are the final central outflow neurons in the autonomic control of sympathetic activity. Cell bodies within the pons and medulla oblongata play a vital role in the control of the cardiovascular system via regulating the activity of SPN (34, 40). The rostral ventrolateral medulla (RVLM) is the key brain stem structure that regulates tonic and reflex pathways that in turn control sympathetic activity (53, 58). Other key regulatory cardiovascular nuclei are found in the hypothalamus. In particular, the paraventricular nucleus (PVN) contains neurons that synthesize many peptides and project to the RVLM and the spinal cord where they are able to affect sympathetic outflow (56,57,72).Bombesin is a 14-amino-acid peptide originally isolated from the skin of the European discoglossid frog Bombina bombina (14). Bombesin is involved in many physiological actions, including gastric acid secretio...

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Somatostatin selectively ablates post-inspiratory activity after injection into the Bötzinger complex

Cited by 52 publications

References 58 publications

Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons

Patterning of somatosympathetic reflexes reveals nonuniform organization of presympathetic drive from C1 and non-C1 RVLM neurons

Peptides, Serotonin, and Breathing

Intrathecal bombesin is sympathoexcitatory and pressor in rat

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