Central effects of baroreceptor activation in humans: attenuation of skeletal reflexes and pain perception.

Abstract

Activating (4), induce synchronization of the electroencephalogram (5), increase cortical positivity (6), blunt pain sensations (7), reduce anxiety (8, 9), and induce sleep (10) or even clinically significant syncope (11). Arousing emotional and pain stimuli elevate blood pressure (12)(13)(14)(15)(16)(17)(18), and the central nervous system (CNS) inhibitory effects ofbarostimulation most simply can be seen to provide supplementary negative feedback, which, along with cardioinhibition and vasodilatation, helps to restore excessively elevated blood pressure to a safer level. Dworkin et al. (19) reported that rats escape from and avoid a mildly aversive trigeminal nucleus stimulus to a lesser degree when their blood pressure is pharmacologically elevated and that the effect can be abolished by denervation of the baroreceptors. They also showed that the impaired avoidance behavior persists into extinction, suggesting that, in addition to pain perception, anxiety is affected. In an extensive series of experiments using more conventional pain stimuli, Randich and Maixner (20) Abbreviations: CNS, central nervous system; CSPP, carotid sinus pulse pressure; PRES, phase-related external suction; EMG, electromyographic or electromyogram; G-G, Greenhouse-Geisser. ITo whom reprint requests should be addressed. 6329The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

The role of ischaemia and pain in the blood pressure response to exercise stress testing in patients with coronary heart disease

“…Although the current study suggests that the baroreflex may be the mechanism linking pain and blood pressure, our study design prevents us from determining whether this is due to a peripheral or central effects. Although previous research, in non-exercise settings, has suggested a central effect of baroreflex stimulation, [36][37][38] it is also possible that there may be a direct peripheral mechanism, a pathway that cannot be discounted by the current study. This is further complicated by the inherent problems of measuring spontaneous baroreflex sensitivity during exercise (i.e., the inability to measure the full function curve).…”

“…In concordance with this, previous research has found links between baroreflex sensitivity and the hypertension-hypoalagesia phenomenon. [36][37][38] For example, cardiac cycle synchronized acute baroreceptor stimulation 37 and natural activation of baroreceptors 36 produced decreased pain perception in humans. However, it is also possible that other mechanisms, possibly in conjunction with baroreflex dysregulation, may play a role in the blood pressure-pain relationship.…”

Psychophysiology of arterial baroreceptors and the etiology of hypertension

“…Based on the observation of arousal and pain dampening exerted through baroreceptor activation, Dworkin, Rau, Elbert and colleagues (Dworkin, 1988;Rau and Elbert, 1993;Elbert et al, 1994;Dworkin et al, 1994Dworkin et al, , 2000 advanced the model of 'learned hypertension'. This theory predicts that learning mechanisms, and operant conditioning in particular, contribute to blood pressure elevations with a possibly catastrophic outcome.…”

Treatment With Enalapril Modifies the Pain Perception Pattern in Hypertensive Patients

“…[1][2][3][4][5][6] Experimental studies have also demonstrated a link between the baroreceptor function and pain perception. [7][8][9][10][11] Modulatory interactions between pain sensitivity and the cardiovascular system have been reported both in physiological conditions and in patients with various cardiovascular syndromes. Alterations in pain sensitivity and circulating ␤-endorphin, an endogenous opioid-like peptide, were found in hypertensive subjects, patients with shock and heart failure, and subjects with silent myocardial ischemia.…”