Potentiation of the carotid artery occlusion reflex by a cholinergic system in the posterior hypothalamic nucleus

Brezenoff, Henry E.; Carney, Kathleen; Buccafusco, Jerry J.

doi:10.1016/0024-3205(82)90576-8

Cited by 19 publications

(4 citation statements)

References 22 publications

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“…The inhibitory effect of atropine upon the cardiac parasympathetic nerves is thought to have been functionally maintained throughout the experiment, since a bolus injection of atropine administered at the end of the experiment did not increase the HR. Though a baroreflex HR increase can be achieved not only by sympathetic nerve activation but also by cardiac parasympathetic nerve inhibition (Brezenoff et al 1982;Ferrari et al 1991), our results indicated that the CAO-evoked HR increase was controlled by the sympathetic nervous system under our conditions. Even if the HR did not change after SCT it would not mean that the cardiac sympathetic nerve was unaffected by the transection, because the parasympathetic effects could compensate for the HR changes.…”

Section: Discussionmentioning

confidence: 53%

Spinal cord transection inhibits HR reduction in anesthetized rats immersed in an artificial CO2-hot spring bath

Yamamoto

Hashimoto

2006

Int J Biometeorol

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Like humans, the heart rate (HR) of anesthetized rats immersed in CO 2 -water is lower than that when immersed in tap water at the same temperature. To investigate the afferent signal pathway in the mechanism of HR reduction, Wistar rats were anesthetized with urethane and then the spinal cord was transected between T 4 and T 5 . The animals were immersed up to the axilla in a bathtub of tap-water (CO 2 contents:10-20 mg·L -1 ) or of CO 2 -water (965-1400 mg·L -1 ) at 35°C while recording HR, arterial blood pressure, and arterial blood gas parameters (PaCO 2 , PaO 2 , pH). Arterial blood gas parameters did not change during immersion irrespective of CO 2 concentration of the bath water, whereas the HR was reduced in the CO 2 -water bath. The inhalation of CO 2 -mixed gas (5 % CO 2 , 20% O 2 , 75 % N 2 ) resulted in increased levels of blood gases and an increased HR during immersion in all types of water tested. The HR reduction observed in sham transected control animals immersed in CO 2 -water disappeared after subsequent spinal cord transection. These results show that the dominant afferent signal pathway to the brain, which is involved in inducing the reduced HR during immersion in CO 2 -water, is located in the neuronal route and not in the bloodstream.

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Section: Discussionmentioning

confidence: 53%

Spinal cord transection inhibits HR reduction in anesthetized rats immersed in an artificial CO2-hot spring bath

Yamamoto

Hashimoto

2006

Int J Biometeorol

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“…Earlier studies showed that the pressor effect of bilateral carotid occlusion was greater after central or systemic administration of physostigmine. 8,17 Caputi et al demonstrated an upward shift in baroreflex HR responses without changes in range or gain following intracerebroventricular injection of physostigmine. 16 A limitation of the present study was that pretreatment with mATR to block peripheral mAChR precluded analysis of vagally mediated HR responses.…”

Section: Padley Et Al Cholinergic Inputs To Rvlm In Central Commandmentioning

confidence: 99%

“…[7][8][9][10][11][12][13][14][15][16][17][18] Systemic or central administration of acetylcholinesterase inhibitors or muscarinic agonists increases blood pressure, 7-11 lowers body temperature, 12 and alters respiration. 13,14 Pressor responses can be evoked via activation of muscarinic receptors (mAChR) within several cardiovascular nuclei, including the posterior hypothalamus, 7 nucleus of the solitary tract, 15 and rostral ventrolateral medulla (RVLM).…”

Section: ;100:284-291)mentioning

confidence: 99%

“…10,11 Effects of central mAChR activation on cardiovascular reflexes are less well understood. 8,16,17 Sympathoexcitatory and hypertensive effects of intravenously administered physostigmine are largely mediated by excitation of RVLM neurons. 10,11,18 The RVLM generates basal sympathetic vasomotor activity and is a critical synaptic relay in cardiovascular reflexes.…”

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confidence: 99%

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Central Command Regulation of Circulatory Function Mediated by Descending Pontine Cholinergic Inputs to Sympathoexcitatory Rostral Ventrolateral Medulla Neurons

Padley

Kumar

et al. 2007

Circulation Research

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Abstract-Central command is a feedforward neural mechanism that evokes parallel modifications of motor and cardiovascular function during arousal and exercise. The neural circuitry involved has not been elucidated. We have identified a cholinergic neural circuit that, when activated, mimics effects on tonic and reflex control of circulation similar to those evoked at the onset of and during exercise. Central muscarinic cholinergic receptor (mAChR) activation increased splanchnic sympathetic nerve activity (SNA) as well as the range and gain of the sympathetic baroreflex via activation of mAChR in the rostral ventrolateral medulla (RVLM) in anesthetized artificially ventilated SpragueDawley rats. RVLM mAChR activation also attenuated and inhibited the peripheral chemoreflex and somatosympathetic reflex, respectively. Cholinergic terminals made close appositions with a subpopulation of sympathoexcitatory RVLM neurons containing either preproenkephalin mRNA or tyrosine hydroxylase immunoreactivity. M2 and M3 receptor mRNA was present postsynaptically in only non-tyrosine hydroxylase neurons. Cholinergic inputs to the RVLM arise only from the pedunculopontine tegmental nucleus. Chemical activation of this region produced increases in muscle activity, SNA, and blood pressure and enhanced the SNA baroreflex; the latter effect was attenuated by mAChR blockade. These findings indicate a novel role for cholinergic input from the pedunculopontine tegmental nucleus to the RVLM in central cardiovascular command. This pathway is likely to be important during exercise where a centrally evoked facilitation of baroreflex control of the circulation is required to maintain blood flow to active muscle. (Circ Res. 2007;100:284-291.)Key Words: baroreflex Ⅲ exercise Ⅲ chemoreflex Ⅲ somatosympathetic A distinct pattern of tonic and reflex cardiovascular adjustments is mediated by central command to ensure appropriate muscle and organ perfusion during different arousal or behavioral states, such as sleep and exercise. [1][2][3] Limited evidence implicates some regions within the pons and hypothalamus that could provide descending input to cardiovascular control sites 4 -6 ; however, the neural circuitry and neurotransmitters involved are yet to be elucidated.Activation of the central cholinergic system has a profound effect on cardiovascular and other autonomic functions. [7][8][9][10][11][12][13][14][15][16][17][18] Systemic or central administration of acetylcholinesterase inhibitors or muscarinic agonists increases blood pressure, 7-11 lowers body temperature, 12 and alters respiration. 13,14 Pressor responses can be evoked via activation of muscarinic receptors (mAChR) within several cardiovascular nuclei, including the posterior hypothalamus, 7 nucleus of the solitary tract, 15 and rostral ventrolateral medulla (RVLM). 10,11 Effects of central mAChR activation on cardiovascular reflexes are less well understood. 8,16,17 Sympathoexcitatory and hypertensive effects of intravenously administered physostigmine are largely mediated by ...

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Anatomical substrates of cholinergic‐autonomic regulation in the rat

Ruggiero¹,

Giuliano²,

Anwar³

et al. 1990

J of Comparative Neurology

194

107

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1) Cholinergic perikarya and putative terminal fields, overlap structures that are rich in cholinoreceptors and express autonomic, neuroendocrine, or behavioral responsivity to central cholinergic stimulation (PHN, NTS, RVL). The role of ACh in most immunolabeled areas, however, has yet to be determined. Overall, these data support the concept that cholinergic agents act at multiple sites in the CNS and with topographic specificity.(ABSTRACT TRUNCATED AT 400 WORDS)

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Potentiation of the carotid artery occlusion reflex by a cholinergic system in the posterior hypothalamic nucleus

Cited by 19 publications

References 22 publications

Spinal cord transection inhibits HR reduction in anesthetized rats immersed in an artificial CO2-hot spring bath

Spinal cord transection inhibits HR reduction in anesthetized rats immersed in an artificial CO2-hot spring bath

Central Command Regulation of Circulatory Function Mediated by Descending Pontine Cholinergic Inputs to Sympathoexcitatory Rostral Ventrolateral Medulla Neurons

Anatomical substrates of cholinergic‐autonomic regulation in the rat

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