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At least 19 recordsLinked to original sources
PubMed1978

[Vital microscopy and histochemical study of the autonomic nervous system of the small intestine in animals with thermal burns].

By means of vital microscopy a possibility of histochemical detection of redox enzymes and of study of changes in their activity in intramural nerve plexuses of the small intestine on a live animal was demonstrated. Severe thermal trauma induced a disturbance of permeability of mitochondrial membranes of the Auerbach's plexus nerve cells; as a result, there was a change in the activity of redox enzymes localized within the mitochondria. Lumbar novocain block performed soon after the burn trauma normalized the state of the mitochondrial membranes of the nerve cells.

Animals↗
PubMed1992

Somatosensory and autonomic deficiencies following trauma in man; evaluation of symptomatology by studying peripheral neural correlates and induced tissue reactions.

Careful clinical and experimental studies in well-diagnosed groups of selected patients can give valuable information concerning unknown mechanisms involved in certain disease states. In particular, microneurographic techniques can be applied to assess the underlying neural pathophysiology. It is anticipated that future studies performed along these guidelines will contribute to an improved diagnosis and/or therapy in a number of clinical conditions.

Adult↗
PubMed1976

Hemodynamics of hyperthyroidism. The effects of autonomic nervous blocking and anti-thyroid drug treatment.

This work was intended to analyze the sympathetic and parasympathetic factors affecting the hemodynamics of hyperthyroidism. Seven patients with hyperthyroidism, diagnosed based on the determinations of BMR, 131I-uptake, T3-resin sponge uptake (T3-RSU), and serum level of thyroxine (T4) were subjected to the study. The hemo-dynamic estimation was done (1) at rest, (2) after vagus blocking by the injection of 0.04 mg/Kg b.wt. atropine and 0.2 mg/Kg b.wt. propranolol before (hyperthyroid state=H) and after (euthyroid state=E) anti-thyroid drug therapy. Cardiac output was measured by the dye-dilution method, and the valve was calculated according to the standard Hamilton formula. The following results were obtained. (1) The vagal tone is lower in H than in E, on the other hand, sympathetic beta-receptor tone is higher in H than in E. (2) The sympathetic alpha-receptor tone in H may be equivalent to that in E. (3) There might exist inotropic factors which affect the hemo-dynamics, other than autonomic nervous system in H.

Adult↗
PubMed1979

The autonomic margins of safety of metocurine and d-tubocurarine in the cat.

The potencies of metocurine and d-tubocurarine for neuromuscular and autonomic blockade and histamine release were determined in cats anesthetized with chloralose and pentobarbital. The autonomic margins of safety of these drugs were determined by measuring the ratios of ED50 for sympathetic block to ED95 for neuromuscular block; ED50 for vagal block to ED95 for neuromuscular block; ED50 for histamine release to ED95 for neuromuscular block. Metocurine is 14 times more potent than d-tubocurarine as a neuromuscular blocking agent in the cat, but its autonomic blocking action is three times weaker than the of d-tubocurarine and its histamine-releasing action is less than half that of d-tubocurarine. The combination of higher neuromuscular blocking potency and weaker autonomic effect gives metocurine a much higher autonomic margin of safety than d-tubocurarine in the cat.

Animals↗
PubMed1975

Estimation of non-autonomic and autonomic components of iliac bed vascular resistance in renal hypertensive rabbits.

Iliac bed vascular resistance (IVR) was measured before and after pharmacological block of the autonomic effectors in unanaesthetized renal hypertensive and normotensive rabbits with previously implanted Doppler flowmeters. This permitted partitioning the resting IVR into a non-autonomic component (ie, steady-state IVR after block) and an autonomic component (ie, resting IVR minus non-autonomic IVR). When IVR was measured at the same mean arterial pressure (MAP) before and after block in each animal, the increase in estimated non-autonomic IVR accounted entirely for the rise in resting IVR in renal hypertensive rabbits. However, if IVR measurements after block were made at a lower MAP than before block, the estimated non-autonomic and autonomic components were both significantly increased in renal hypertensive rabbits. It is concluded that in the latter experiment non-autonomic IVR in renal hypertension was underestimated, whilst the autonomic component was overestimated. The rise in non-autonomic IVR in renal hypertension was partly due to structural changes in the iliac bed, since IVR remained higher in hypertensive than in normotensive rabbits after abolishing smooth muscle tone with vasodilator drugs.

Animals↗
PubMed1992

Afferent control of vasopressin and renin release during haemorrhage in normal and autonomically blocked rabbits.

1. The role of the arterial and cardiac baroreceptors on the arginine vasopressin (AVP) and plasma renin activity (PRA) responses to haemorrhage was studied in conscious rabbits. They were bled at a rate of approximately 3% of their blood volume (BV)/min, both when the autonomic nervous system (ANS) was intact and during ANS blockade, which markedly enhances the AVP response due to the much greater haemodynamic disturbance. Under each condition of ANS function 2 x 2 factorial analysis was performed, each with four groups of rabbits, including animals with both sets of baroreceptors working, one or other set working and neither set working. 2. With intact ANS, haemorrhage had to be terminated at different times in the four groups. This presents problems for factorial analysis due to differences in the relationship between plasma AVP (or PRA) and release rate. A method for overcoming this was developed by extrapolating the BV-log AVP curves to a common time from the start of bleeding. 3. Under both conditions of ANS function the arterial and cardiac baroreceptors together accounted for 90-95% of the rise in AVP during haemorrhage. With normal ANS function, the rise in AVP was about 70% through cardiac (probably ventricular) baroreceptors (P = 0.01) and about 30% through arterial baroreceptors (P = 0.08). This compares with an earlier study at a rate of bleeding of 1.8% BV/min, where the entire drive came from the cardiac receptors. During ANS blockade, plasma AVP was enhanced approximately five-fold, which was mostly mediated through the arterial baroreceptors, but the cardiac baroreceptor component was also greater; arterial/cardiac baroreceptor drive was 2/1. 4. Baroreflexes played no role in renin release during haemorrhage, but the experiments with ANS blockade suggest that a hormonal factor, which was related to the cardiac innervation, may limit the rise in PRA in the latter part of haemorrhage.

Afferent Pathways↗
PubMed1976

Electrophysiological techniques for the study of urethral and vesical innervation.

A new electrophysiological technique for the study of urethral and vesical innervation is reported. The method gives valuable information on the structural integrity and function of two of the reflex arcs involved in micturition. Normal and pathological patterns are described, illustrating the diagnostic value of the method in the assessment of neurogenic disturbances of bladder and urethral function.

Anal Canal↗
PubMed1977

Autonomic hyperreflexia: intraoperative control with pentolinium tartrate.

Autonomic hyperreflexia (AH) is a clinical syndrome associated with the development of severe hypertension. It usually occurs in patients with high-level chronic spinal cord injury, and in response to stimuli associated with the distension of a hollow viscus. Protection against AH by the prophylactic use of pentolinium tartrate (Ansolysen) in doses of 10-15 mg was evaluated in a controlled study of unanaesthetized patients who were either quadriplegic or paraplegic and who were undergoing rectal and bladder surgical procedures. When compared with the control group, the systolic and diastolic arterial pressures during operation were significantly less (P less than 0.05) and remained near normal in the pretreated patients. The use of pentolinium to prevent or control AH during surgical procedures in patients with chronic spinal cord damage is a simple alternative to spinal or general anaesthesia.

Adult↗
PubMed1977

Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

We studied the autonomic control of resting heart rate of systemic and pulmonary vascular blood pressures (BP) in chronically instrumented neonatal lambs 1-8 weeks of age. The maximum response to ganglionic blockade and sympathetic and parasympathetic antagonists was taken as an index of the magnitude of the total neural, adrenergic, and cholinergic tones. The reactivity of the circulatory parameters to adrenergic and cholinergic agonists also was investigated. All findings were compared with those in adult nonpregnant sheep studied concomitantly and with data previously obtained from term fetal lambs. The results of our studies show: (1) resting heart rate declines spontaneously throughout the 8 weeks of neonatal life approaching that of adult sheep; (2) the progressive bradycardia is not related to changes in the parasympathetic or sympathetic tone; (3) resting systemic BP is under strong neurohumoral control during the first two to three weeks of neonatal life; the control decreases progressively, becoming similar to that of adult sheep; (4) resting pulmonary artery pressure of neonatal and adult sheep has no neurohumoral control; (5) the systemic BP response of the neonate to autonomic agonists is greater than that of the term fetus and is similar to that of the adult; (6) in neonatal and adult sheep, compared to the term fetus, the pressor response to norepinephrine is accompanied by a baroreceptor-mediated bradycardia, and acetylcholine-induced systemci hypotension is accompanied by a "paradoxical" tachycardia mediated through beta-adrenergic stimulation; (7) in contrast to our finding for the fetus, the pulmonary vascular pressure of neonatal and adult sheep is unresponsive to autonomic agonists.

Acetylcholine↗
PubMed1992

The autonomic nervous system modulates dry air-induced constriction in the canine lung periphery.

To determine the modulatory role of the autonomic nervous system on dry air-induced bronchoconstriction (AIB) in the canine lung periphery, we examined the effect of cholinergic, alpha- and beta-adrenergic, and total autonomic ganglionic blockade on AIB. Pretreatment with atropine significantly attenuated AIB by approximately 30%, indicating that AIB is partially mediated via a vagal reflex. Pretreatment with either phentolamine or propranolol did not affect AIB, indicating that alpha- and beta-adrenoceptors, respectively, were not activated in response to dry air challenge. In contrast, pretreatment with hexamethonium significantly potentiated AIB. In addition, exogenous vasoactive intestinal peptide (VIP), a potential neurotransmitter for the nonadrenergic-noncholinergic (NANC) inhibitory system, significantly inhibited AIB. We conclude that (1) neither alpha- or beta-adrenergic efferents are activated during dry air challenge, (2) total autonomic blockade potentiates the response to dry air, and (3) VIP attenuates AIB. Based on these observations, we speculate that NANC inhibitory activity may be stimulated during dry air challenge and antagonizes AIB.

Animals↗
PubMed1979

Lack of cardiovascular effects of delta-9-tetrahydrocannabinol in chemically denervated men.

We have previously reported that 25 micrograms/kg of intravenous (i.v.) delta-9-tetrahydrocannabinol (delta-9-THC) produces marked increases in heart rate, prolongation of left ventricular ejection time corrected for heart rate (LVETc), and a shortening of the pre-ejection period in normal volunteers. Beta-adrenergic blockade partially attenuates these responses. To elucidate further the mechanism of action of delta-9-THC, we gave 10 normal volunteers 0.1 mg/kg of i.v. propranolol and 2 mg of i.v. atropine before they received 25 micrograms/kg of i.v. delta-9-THC. Systolic time intervals were compared in the denervated subjects before and after delta-9-THC. Post delta-9-THC responses were measured at a time approximating peak psychologic high. Mean +/- SEM heart rate before and after delta-9-THC was 89 +/- 4 and 87 +/- 3 beats/min (NS); mean +/- SEM pre-ejection period before and after delta-9-TCH was 107 +/- 5 and 109 +/- 4 ms (NS); and mean +/- SEM LVETc before and after delta-9-THC was 433 +/- 6 and 429 +/- 6 ms (NS). Since previous denervation of our subjects with atropine and propranolol totally abolished changes in heart rate and systolic time intervals, the cardiac effects of delta-9-THC appear to be mediated totally via the autonomic nervous system, probably reflecting direct central nervous system stimulation.

Adult↗
PubMed1992

Some aspects of vascular pharmacology of frog (Rana tigrina).

Vascular autonomic receptors in amphibians exhibit difference from more evolved mammalian species. Vascular perfusion studies in frog indicate constrictions by prominent muscarinic but rudimentary nicotinic constrictive regulation by cholinergic systems. Difference from classical effect-patterns of pharmacological interventions, observed in the study, make room to visualise complexity of additional regulatory mechanisms.

Adrenergic alpha-Antagonists↗
PubMed1992

[Mitral valve prolapse. Atrial stimulation, ajmaline test and "pharmacological denervation" in the evaluation of ventricular repolarization].

In patients with mitral valve prolapse syndrome (MVP) various electrophysiological abnormalities occur. There are convergent opinions concerning QT distance variability and the influence of autonomic nervous system on ventricular repolarization in this syndrome. In 38 MVP patients (group I) and 24 subjects without this abnormality (group II) ecg was recorded during transvenous right atrial pacing at baseline, after ajmaline administration and after pharmacological autonomic blockade (atropine + propranolol). The following ventricular repolarization parameters were analysed: QTe (distance to the end of T wave), JTe (distance between J point and the end of T wave--so called "pure repolarization"), QTdys (repolarization dispersion) and the corrected QTc.QTe during 90/min right atrial pacing was significantly shorter than QTc in both groups. QTc was abnormally prolonged (above 440 msec) in MVP group. Ajmaline administration prolonged QTe in group II only, whereas autonomic blockade resulted in marked shortening of QTe in MVP group. QTdys was significantly prolonged only after ajmaline administration in group II. Based on above results, the following conclusions are made: 1) Right atrial pacing technique may be used for calculating standardized QT distance, an alternative to corrected QT. 2) Ajmaline test is useless in ventricular repolarization estimations in MVP patients. 3) In MVP patients the influence of adrenergic system on ventricular repolarization at rest appears to be greater than in non-MVP subjects.

Adolescent↗