Role of beta adrenoceptors in metabolic and cardiovascular responses of cold exposed humans

To investigate the role of the paraventricular (PAH) and supraoptic (SON) nuclei in regulation of the cardiovascular system experiments were done in 26 cats anesthetized with alpha-chloralose, paralyzed, and artificially ventilated. Electrical stimulation of histologically verified sites in the region of the PAH and SON elicited increases in arterial pressure in bilaterally vagotomized animals and increases in heart rate both in spinal (C2) animals and in animals bilaterally vagotomized, In addition, stimulation of either the PAH or SON inhibited the reflex vagal bradycardia elicited by stimulation of the carotid sinus nerve (CSN) and bilateral lesions of these areas increased the magnitude of the response. On the other hand, stimulation and lesions of these hypothalamic regions did not alter the magnitude of the cardiovascular responses to stimulation of the aortic depressor nerve. These results demonstrate that stimulation of the PAH and SON elicit cardiovascular responses due to reciprocal changes in activity of the parasympathetic and sympathetic nervous systems and that these structures maintain a tonic inhibitory influence on the heart rate component of the CSN reflex.

Download Full-text

Ouabain- and central sodium-induced hypertension depend on the ventral anteroventral third ventricle region

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1999.276.1.h63 ◽

1999 ◽

Vol 276 (1) ◽

pp. H63-H70 ◽

Cited By ~ 8

Author(s):

Shereeni J. Veerasingham ◽

Frans H. H. Leenen

Keyword(s):

Hypertonic Saline ◽

Wistar Rats ◽

Third Ventricle ◽

Cardiovascular Responses ◽

Ibotenic Acid ◽

Air Jet ◽

Artificial Cerebrospinal Fluid ◽

Induced Hypertension ◽

Chronic Infusion

To examine the role of the ventral anteroventral third ventricle (vAV3V) in the hypertension induced by chronic subcutaneous ouabain and intracerebroventricular hypertonic saline, neurons in this area were destroyed by microinjection of an excitotoxin, ibotenic acid. Sham-operated or lesioned Wistar rats were administered ouabain (50 μg/day) or placebo for 3 wk from subcutaneously implanted controlled release pellets or artificial cerebrospinal fluid (CSF) or CSF containing 0.8 mol/l NaCl (5 μl/h) infused intracerebroventricularly for 2 wk. At the end of the experiment, mean arterial pressure (MAP) and heart rate at rest and in response to ganglionic blockade by intravenous hexamethonium (30 mg/kg) were assessed. In rats infused with hypertonic saline, responses to air jet stress were also assessed. Baseline MAP in sham-operated rats receiving intracerebroventricular hypertonic saline or subcutaneous ouabain was significantly higher than in control rats (115 ± 1 vs. 97 ± 3 and 121 ± 3 vs. 103 ± 3 mmHg, respectively). vAV3V lesions abolished the increase in MAP elicited by chronic infusion of hypertonic saline or administration of ouabain. Sham-operated rats treated with hypertonic saline or ouabain exhibited significantly enhanced decreases in MAP to hexamethonium, but lesioned rats did not. Rats infused with hypertonic saline demonstrated enhanced responses to air jet stress that were similar in sham-operated and lesioned rats. These results demonstrate that neurons in the vAV3V are essential for the hypertension induced by intracerebroventricular hypertonic saline and subcutaneous ouabain, possibly by increasing sympathetic tone. Cardiovascular responses to air jet stress appear not to be mediated by the vAV3V.

Download Full-text

Role of lateral hypothalamus on fluid, electrolyte, and cardiovascular responses to activation of the MSA

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1994.266.2.r496 ◽

1994 ◽

Vol 266 (2) ◽

pp. R496-R502 ◽

Cited By ~ 1

Author(s):

A. S. Haibara ◽

W. A. Saad ◽

J. V. Menani ◽

L. A. Camargo ◽

A. Renzi

Keyword(s):

Water Intake ◽

Lateral Hypothalamus ◽

Cardiovascular Responses ◽

Electrolytic Lesion ◽

Opioid Agonist ◽

Inhibitory Mechanisms ◽

Pressor Responses ◽

Medial Septal Area ◽

Opiate Agonist

In this study we investigated the influence of electrolytic lesion or of opioid agonist injections into the lateral hypothalamus (LH) on the dipsogenic, natriuretic, kaliuretic, antidiuretic, pressor, and bradycardiac effects of cholinergic stimulation of the medial septal area (MSA) in rats. Sham- and LH-lesioned male Holtzman rats received a stainless steel cannula implanted into the LH. Other groups of rats had cannulas implanted simultaneously into the MSA and LH. Carbachol (2 nmol) injection into the MSA induced water intake, pressor, and bradycardic responses. LH lesion reduced all of these effects (1-3 and 15-18 days). Previous injection of synthetic opiate agonist, FK-33824 (100 ng), into the LH reduced the water intake, natriuresis, kaliuresis, and pressor responses induced by carbachol injected into the MSA. These data show that both electrolytic lesion or injection of an opiate agonist in the LH reduces the fluid-electrolyte and cardiovascular responses to cholinergic activation of the MSA. The involvement of LH with central excitatory and inhibitory mechanisms related to fluid-electrolytic and cardiovascular control is suggested.

Download Full-text

Role of Beta Adrenoceptors in the Control of Myocardial O2 Supply/Consumption Heterogeneity

Analysis and Simulation of the Cardiac System — Ischemia ◽

10.1201/9781003068341-29 ◽

2020 ◽

pp. 319-332

Author(s):

Harvey R. Weiss ◽

Mary E. Upsher

Keyword(s):

Beta Adrenoceptors ◽

O2 Supply

Download Full-text

Role of pre–extubation fentanyl in mastectomy: a randomized, controlled, double–blind study

Anaesthesia, Pain & Intensive Care ◽

10.35975/apic.v25i2.1462 ◽

2021 ◽

Vol 25 (2) ◽

Author(s):

Ahmed Salman ◽

Norma Osama Zayed ◽

Ahmed Mansour ◽

Ramy Howaidi ◽

Ahmed Gamaleldin Foly ◽

...

Keyword(s):

Short Form ◽

Cardiovascular Responses ◽

Blind Study ◽

Double Blind Study ◽

Double Blind ◽

Randomized Controlled ◽

Arterial Blood ◽

Extubation Time ◽

Significant Difference

Background: Both tracheal intubation and extubation are associated with dangerous consequences such as tachycardia, hypertension, myocardial ischemia and arrhythmias. The aim was to evaluate pre–extubation two different doses of fentanyl on hemodynamic stabilization and delayed recovery in mastectomy. Methodology: The randomized controlled double–blind study was conducted on 126 patients aged 16–60 years, with controlled hypertension, receiving chemotherapy before surgery and underwent mastectomy for breast cancer. Patients were randomly allocated into 3 equal groups. Before extubation, patients received 10 ml saline in group (C), 1 µg/kg fentanyl in Group–F1: and 2 µg/kg fentanyl in Group–F2. Mean arterial blood pressure (MAP) and heart rate (HR) were recorded at T1 (after maintenance of anesthesia), T2 (after giving the test drug), T3 (immediately after extubation), T4 (5 min. after extubation) and T5 (15 min after extubation). Results: MAP was significantly lower in fentanyl groups compared to Group–C at T2 and T3 without significant deference between fentanyl groups. HR was significantly lower in fentanyl groups compared to Group–C and in Group–F2 compared to Group–F1 at T3, T4 and T5. Time of extubation was significantly prolonged in Group–F2 compared to Group–F1 and Group–C without a significant difference between Group–F1 and Group–C. Conclusions: Pre–extubation fentanyl 1 µg/kg blunted cardiovascular responses to extubation without respiratory depression or prolonged recovery. Pre–extubation fentanyl 2 µg/kg provide more control in HR but with delay in the extubation time compared to 1 µg/kg of fentanyl. Key words: Pre–Extubation, Fentanyl, Mastectomy, Hemodynamics, Recovery Preregistration: The study was registered in the Ethical Committee of Faculty of Medicine, Cairo University, Cairo, Egypt (approval number: 281) Citation: Salman A, Zayed NO, Mansour A, Howaidi R, Foly AG, ElSharkawy MS, Abdelgalil AS. Role of pre–extubation fentanyl in mastectomy: a randomized, controlled, double–blind study. Anaesth. pain intensive care 2021;25(2):143-149. DOI: 10.35975/apic.v25i2.1462. Abbreviations: CST=Craniosacral therapy; SMT=Sensorimotor training; NCLBP=Nonspecific chronic low back pain; VAS=Visual analogue scale; ODI=Oswestry disability index, BDI-II=Beck depression inventory-II, and SF-36=Short Form-36; CSF=cerebral spinal fluid; CSS=craniosacral system; PRM=primary respiratory movements Received: 27 June 2020, Reviewed: 24 July 2020, Accepted: 27 July 2020

Download Full-text

Role of nitric oxide-containing factors in the ventilatory and cardiovascular responses elicited by hypoxic challenge in isoflurane-anesthetized rats

Journal of Applied Physiology ◽

10.1152/japplphysiol.00842.2013 ◽

2014 ◽

Vol 116 (11) ◽

pp. 1371-1381 ◽

Cited By ~ 3

Author(s):

James P. Mendoza ◽

Rachael J. Passafaro ◽

Santhosh M. Baby ◽

Alex P. Young ◽

James N. Bates ◽

...

Keyword(s):

Nitric Oxide ◽

Heart Rate ◽

Cardiovascular Responses ◽

Vital Role ◽

Initial Increase ◽

Ventilatory Responses ◽

Arterial Blood ◽

Anesthetized Rats ◽

Before And After

Exposure to hypoxia elicits changes in mean arterial blood pressure (MAP), heart rate, and frequency of breathing (fr). The objective of this study was to determine the role of nitric oxide (NO) in the cardiovascular and ventilatory responses elicited by brief exposures to hypoxia in isoflurane-anesthetized rats. The rats were instrumented to record MAP, heart rate, and fr and then exposed to 90 s episodes of hypoxia (10% O2, 90% N2) before and after injection of vehicle, the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME), or the inactive enantiomer d-NAME (both at 50 μmol/kg iv). Each episode of hypoxia elicited a decrease in MAP, bidirectional changes in heart rate (initial increase and then a decrease), and an increase in fr. These responses were similar before and after injection of vehicle or d-NAME. In contrast, the hypoxia-induced decreases in MAP were attenuated after administration of l-NAME. The initial increases in heart rate during hypoxia were amplified whereas the subsequent decreases in heart rate were attenuated in l-NAME-treated rats. Finally, the hypoxia-induced increases in fr were virtually identical before and after administration of l-NAME. These findings suggest that NO factors play a vital role in the expression of the cardiovascular but not the ventilatory responses elicited by brief episodes of hypoxia in isoflurane-anesthetized rats. Based on existing evidence that NO factors play a vital role in carotid body and central responses to hypoxia in conscious rats, our findings raise the novel possibility that isoflurane blunts this NO-dependent signaling.

Download Full-text