Reflex effect

The toxicity of H. procumbens is considered extremely low. To date, there have been no reported side-effects following its use. However, this plant is said to have oxytocic properties and should be avoided in pregnancy. In addition, due to its reflex effect on the digestive system, it should be avoided in patients with gastric or duodenal ulcers. 

The pharmacologic actions of phenoxybenzamine are primarily related to antagonism of -receptor-mediated events. The most significant effect is attenuation of catecholamine-induced vasoconstriction. While phenoxybenzamine causes relatively little fall in blood pressure in normal supine individuals, it reduces blood pressure when sympathetic tone is high, eg, as a result of upright posture or because of reduced blood volume. Cardiac output may be increased because of reflex effects and because of some blockade of presynaptic k2 receptors in cardiac sympathetic nerves. 

This is a manifestation of the reflex effect, see Sandris, C., Ourissson, G. Bull. Soc. Chim. France 7958, 1529 and subsequent references. 

Vatner, S., Higgins, CB, Milland, RW, and Franklin, D. 1972. Direct and reflex effects of nitroglycerin on coronary and left ventricular dynamics in conscious dogs. J Clin Invest 51 2872-82. 

Baroreceptor reflex effects, such as tachycardia, palpitation, and arrhythmia effects due to decreased tension, such as edema, and postural hypotension and effects due to decreased oxygen delivery, such as peripheral ischemia, dizziness, syncope, vertigo, and lightheadedness. 

Due to its marked variability, it is impossible to state quantitatively whether stimulation by caffeine is affected by sino-aortic denervation. It is clear, however, that good stimulation can be obtained with caffeine in an animal after section of the aortic and carotid sinus nerves. These experiments seem to prove that caffeine acts centrally but they do not eliminate some shght reflex effects by way of the sino-aortic nerves. 

A decrease in heart rate caused by indirect reflex effect An increase in heart rate caused by direct cardiac action An increase in heart rate caused by indirect reflex action No change in heart rate... 

Paintal AS (1969) Mechanism of stimulation of type J pulmonary receptors, J Physiol 203 511-532 Paintal AS (1973) Vagal sensory receptors and their reflex effects. Physiol Rev 53 159-227 Pinto A, Yanai M, Sekizawa K, Aikawa T, Sasaki H (1995) Conditioned enhancement of cough response in awake guinea pigs, Int Arch Allergy Immunol 108 95-98... 

Chizh BA, Hies P (2001) P2X receptors and nociception. Pharmacol Rev 53(4) 553-68 Choudry NB, Fuller RW, Pride NB (1989) Sensitivity of the human cough reflex effect of inflammatory mediators prostaglandin E2, bradykinin, and histamine. Am Rev Respir Dis... 

Deep, V., M. Singh, and K. Ravi. 2001. Role of vagal afferents in the reflex effects of capsaicin and lobeUne in monkeys. Respir. Physiol. 125(3) 155-168. 

Harper AA, Kidd C, Scratcherd T. Vago-vagal reflex effects on gastric and pancreatic secretion and gastrointestinal motility. J Physiol Lond 148 417-436, 1959. 

Our laboratory has recently investigated the reflex effects of carotid sinus hypertension on the coronary circulation (Ito and Feigl, 1984a). The carotid sinuses were vascularly isolated and perfused with a servo controlled pressure pump. The aortic depressor nerves were cut bilaterally to prevent aortic arch baroreceptor reflexes from buffering carotid sinus reflexes. The left main coronary artery was perfused at constant pressure, and the ventricles were paced at a constant rate following the production of heart block in a closed-chest preparation. Aortic pressure was stabilized with a pressure reservoir and propranolol was administered to block reflex sympathetic effects to the myocardium. Step increases in carotid sinus pressure resulted in graded reflex coronary vasodilation accompanied by increases in coronary sinus oxygen tension. Atropine administration demonstrated that the major portion of the reflex vasodilation was due to parasympathetic activation. These results indicate that parasympathetic coronary vasodilation is part of the carotid sinus baroreceptor reflex. 

Hashimoto K, Igarashi S, Uei I, Kumakura S (1964) Carotid chemoreceptor reflex effects on coronary flow and heart rate. Am J Physiol 206 536-540... 

The ability to sense and respond to hypoxia is present in all taxa and represents a fundamental physiological requirement for O2 at the subcellular level. An examination of the phytogeny of O2 chemoreception reveals interesting trends as well as contradictions. Although there is extensive literature on the reflex effects of 02-chemoreceptor stimulation, there are few neural or cellular studies in organisms other than mammals. Through comparative studies it may be possible to determine... 

The energy-minimization technique has been used to study bicyclo[3,2,11-octane, bicyclo[3,2,l]octan-3-one, and the corresponding a-bromo-ketones. The calculated results are in satisfactory agreement with the observed molecular geometry, but are less reliable in estimating strain energies. The concept of the anti-reflex effect is supported by these results. 

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