Emotions and the peripheral vasomotor system; a review of previous work

Control of the Cutaneous Circulation by the Central Nervous System

The central nervous system (CNS), via its control of sympathetic outflow, regulates blood flow to the acral cutaneous beds (containing arteriovenous anastomoses) as part of the homeostatic thermoregulatory process, as part of the febrile response, and as part of cognitive-emotional processes associated with purposeful interactions with the external environment, including those initiated by salient or threatening events (we go pale with fright). Inputs to the CNS for the thermoregulatory process include cutaneous sensory neurons, and neurons in the preoptic area sensitive to the temperature of the blood in the internal carotid artery. Inputs for cognitive-emotional control from the exteroceptive sense organs (touch, vision, sound, smell, etc.) are integrated in forebrain centers including the amygdala. Psychoactive drugs have major effects on the acral cutaneous circulation. Interoceptors, chemoreceptors more than baroreceptors, also influence cutaneous sympathetic outflow. A major advance has been the discovery of a lower brainstem control center in the rostral medullary raphé, regulating outflow to both brown adipose tissue (BAT) and to the acral cutaneous beds. Neurons in the medullary raphé, via their descending axonal projections, increase the discharge of spinal sympathetic preganglionic neurons controlling the cutaneous vasculature, utilizing glutamate, and serotonin as neurotransmitters. Present evidence suggests that both thermoregulatory and cognitive-emotional control of the cutaneous beds from preoptic, hypothalamic, and forebrain centers is channeled via the medullary raphé. Future studies will no doubt further unravel the details of neurotransmitter pathways connecting these rostral control centers with the medullary raphé, and those operative within the raphé itself. © 2016 American Physiological Society. Compr Physiol 6:1161-1197, 2016.

Atypical antipsychotics cause an acute increase in cutaneous hand blood flow in patients with schizophrenia and schizoaffective disorder

OBJECTIVE

Clinical studies suggest resting thermoregulatory cutaneous vasomotor tone could be increased in schizophrenia, resulting in reduced hand blood flow. In animal models, atypical antipsychotics including clozapine potently inhibit sympathetic neural outflow to the thermoregulatory cutaneous vascular beds. We have now determined whether antipsychotic medication administration is associated with an acute increase in hand blood flow in patients with schizophrenia and schizoaffective disorder, and whether this increase correlates with clinical status.

METHOD

Hand temperature was measured with an infrared camera in 12 patients with chronic schizophrenia or schizoaffective disorder 30 min prior to, then 30 and 60 min following medication. Clinical status was assessed via the Brief Psychiatric Rating Scale (BPRS). Results were compared using regression and repeated measures analysis of variance.

RESULTS

A robust and significant increase in hand temperature (p < 0.001) was observed following antipsychotic administration. The mean increase after 60 min was 4.1 ± 2.4°C. This increase was significantly associated with colder hand temperature prior to medication (p < 0.05; suggestive of increased resting vasoconstriction) and with more severe psychiatric symptoms (p < 0.05).

CONCLUSIONS

Atypical antipsychotics were associated with increased hand blood flow, consistent with inhibition of thermoregulatory sympathetic outflow to the cutaneous vascular bed in patients with schizophrenia and schizoaffective disorder. This increase correlated with symptom severity. Hand temperature increase following antipsychotic medication may therefore be a simple and informative physiological marker of disease activity and potential response in patients with schizophreniform disorders. Given that antipsychotics also inhibit sympathetic outflow to brown adipose tissue, which normally converts energy to heat, future studies should examine whether antipsychotic-induced hand temperature increase is associated with antipsychotic-induced weight gain.

The effect of mirthful laughter on the human cardiovascular system

It has become increasingly recognized and more widely acknowledged during the past several decades, that a complex relationship exists between behavior associated with emotion and the human cardiovascular (CV) system. Early studies focused on the interplay between negative emotions and elevated CV risk, an effect that has in large part been attributed to increased adrenergic activity. Thus, a variety of adverse CV effects ranging from sudden cardiac death triggered by natural disasters such as earthquakes to transient myocardial stunning resulting from heightened sympathetic overload have been identified in response to acute emotional distress. In fact, the biologic interplay between emotion and CV health has been greatly enhanced through studies of the vascular endothelium. As the largest organ in humans, the inner blood vessel lining serves as a conduit for the transfer of blood cells, lipids and various nutrients across the lumen to neighboring tissues. Healthy endothelial cells secrete vasoactive chemicals, most notably endothelial-derived relaxing factor or nitric oxide (NO), that effects smooth muscle relaxation and vessel dilation via a cyclic guanosine monophosphate (cGMP) dependent protein kinase signaling pathway. In addition, endothelial derived NO may reduce vascular inflammation by attenuating or inhibiting leukocyte adhesion and subendothelial transmigration as well as decreasing platelet activation via cGMP mediated pathways. Taken together, studying the endothelium provides an exceptional opportunity to advance our understanding of the potentially important interrelationship between emotions and the vasculature. Premised on the identification of physiological and biochemical correlates, the former was demonstrated after intracoronary administration of acetylcholine yielded paradoxical endothelial vasoconstriction in response to mental stress exercises. More recently, the brachial artery reactivity test (BART) has permitted endothelial function to be assessed in a non-invasive manner. In addition to traditional CV risk factors, exposure to negative emotions including mental stress and depression have been associated with reduced endothelial vasoreactivity as measured by BART. Whether mirthful laughter has the opposite effect garnered consideration following the discovery that mu3 opiate receptors were expressed in the vascular endothelium. Because mirthful laughter induces the release of beta-endorphins which in turn have high affinity for mu3 opiate receptors, we hypothesize that such positive emotions lead to the direct release of NO and associated biological consequences. Indeed, our studies have demonstrated opposing effects on endothelial vasoreactivity between those previously established (e.g., mental stress induced by negative visual and/or auditory stimuli) and those induced after mirthful laughter, thereby providing a potential mechanistic link between positive emotions and beneficial effects on the vasculature. This article reviews the relevant physiology and comments on the potentially wider clinical implications in the integration of this process to improve vascular health.

Clozapine increases cutaneous blood flow and reduces sympathetic cutaneous vasomotor alerting responses (SCVARs) in rats: comparison with effects of haloperidol

RATIONALE

Clozapine inhibits sympathetic outflow to the cutaneous vascular bed. Clozapine reverses hyperthermia and cutaneous vasoconstriction induced by 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) or by lipopolysaccharide (LPS). Clozapine also reverses cutaneous vasoconstriction elicited by exposure to cold. These actions distinguish clozapine from haloperidol. Clozapine could also inhibit sympathetic cutaneous vasomotor alerting responses (SCVARs), vasoconstrictor episodes that reflect emotional/psychological function, and this property might also distinguish clozapine from haloperidol.

OBJECTIVES

Experiments in rats determined whether clozapine and haloperidol inhibit SCVARs, and whether SR46349B (a 5HT2A receptor antagonist), 8-OH-DPAT (a 5-HT1A agonist), L741,626 (a dopamine D2 antagonist) or SCH23390 (a dopamine D1 antagonist) have clozapine-like effects on SCVARs.

METHODS

Mean level and pulse amplitude of the tail artery Doppler flow signal were recorded in conscious freely moving rats before and after alerting stimuli (e.g. tapping the cage), and expressed as a SCVAR index (fall to zero flow implies SCVAR index of 100%, no fall implies 0%).

RESULTS

Clozapine (0.0625-1.0 mg/kg, s.c.) dose-dependently increased resting tail blood flow. After 1 mg/kg, the SCVAR index was 18+/-1%, compared with 83+/-2% after vehicle. SR46349B (0.01-1.0 mg/kg) and 8-OH-DPAT (0.25 mg/kg) had similar but less potent effects on cutaneous blood flow and on SCVARs. Haloperidol (0.005-0.5 mg/kg) and L741,626 (1 mg/kg) had no or little effect on these variables. SCH23390 mildly inhibited SCVARs.

CONCLUSIONS

Clozapine, but not haloperidol, increases resting cutaneous blood flow and decreases SCVARs. Antagonism at 5-HT2A receptors and agonism at 5-HT1A receptors could contribute to these actions.

A behavioral analysis of diaphragmatic breathing and its effects on peripheral temperature

Three young women volunteers were trained through instructional feedback in two breathing procedures: diaphragmatic, derived from Eastern meditative techniques, and thoracic, involving opposite maneuvers. A single-subject reversal design was employed. Physiograph recordings of diaphragmatic expansion and mouth breathing provided the basis for feedback. Peripheral (digital) temperature was time-sampled at 1-min intervals and linear regression lines were fitted to the data. Temperature decreased throughout "normal" (baseline) breathing, probably due to warm outdoor and cool indoor temperatures. For two subjects, temperature during diaphragmatic breathing was generally stable; temperature during thoracic breathing showed significant decreases and did not differ from normal breathing. Within-session reversals showed dramatic changes in temperature as a function of breathing technique, which were maintained at follow-up, for these subjects. Temperature was more labile and decreased regardless of breathing procedure for the third subject. These data support a relationship between respiratory and vasomotor activity, and suggest that breathing strategy may be an uncontrolled variable in temperature biofeedback. It is further suggested that diaphragmatic breathing may facilitate temperature biofeedback or other types of relaxation training.

Noninvasive assessment of the autonomic nervous tone in angina pectoris: an application of digital plethysmography with auditory stimuli

To assess the relationship between autonomic nerve activity and the anginal attack, we examined the daily variation of the autonomic tones employing digital plethysmography with auditory stimuli, and also tested the daily variation of exercise capacity. Thirteen of 45 cases (28.9%) of spontaneous angina, excluding Prinzmetal's angina, complained of typical chest discomfort or pain especially in the morning. They manifested an augmented level of the autonomic nerve activity and positive stress testing. The remainder did not demonstrate these abnormal findings in the morning. For the 13 cases, calcium antagonists were given orally immediately after awakening. This resulted in the complete relief from chest discomfort or pain. These findings suggest that an autonomic imbalance plays an important role in the pathogenesis of this type of anginal attack. Thus, the estimation of the daily variation of autonomic nervous tone would be valuable for the diagnosis and treatment of angina pectoris.

A pilot study of the changes of skin electrical conductance in patients undergoing general anaesthesia and surgery

Change of skin electrical conductance have been monitored from induction of anaesthesia to recovery in two groups of patients. The first group receiving inhalational anaesthesia with halothane and spontaneous respiration demonstrated no changes in response to surgical stimulus. Some patients from the second group receiving muscle relaxation and ventilation with nitrous oxide and oxygen without halothane demonstrated changes in response to surgery. The changes are mediated by the sympathetic nervous system and the technique forms a simple monitor of sympathetic activity during surgery.

Dermatopsychosomatics: classification, physiology, and therapeutic approaches

Psychosomatic dermatology is practiced in some manner by every dermatologist. In spite of this, there has been a virtual void in the literature from the middle 1950s until the present time. The relationship to physiologic phenomena, as well as a classification of psychosomatic dermatology, is reviewed. Dermatologic patients are divided into three groups: the primary group in which the emotional disorder is the primary disease and the cutaneous disorder merely part of its expression; the secondary group in which the basic cause is organic but does not affect the person emotionally in various degrees; and the collaborative group in which the organic causes and emotional disorders combine in different degrees to cause the skin disorder. This paper discusses anxiety and depression along with methods of dermatologic psychosomatic therapy consisting of antianxiety drugs, especially the benzodiazepines, antidepressants, hypnosis, behavior therapy, and the doctor/patient rapport. We conclude that one of the objectives for every dermatologist is to treat the entire patient-the psyche along with the soma.

Minimum intensities of white noise which produce the vasomotor response

Twelve normal hearing awake adult subjects were tested to determine the minimum intensities of white noise which produce a detectable change in digital blood flow. A digital plethysmograph was utilised to detect and record these changes. The stimulus intensity was adjusted in 5 dB increments, beginning at an intensity below voluntary threshold, for a total of four data trials. The range of minimum intensities producing the response was 20 to 60 dB HTL, however, there was no significant variation in the mean intensities required to produce the response from trial to trial (F = 0.48, df-3.30, N.S.). The results support further research into the development of peripheral vascular techniques in determining the presence or absence of hearing for individuals who cannot be tested by voluntary audiometry.

A component analysis of biofeedback induced self-control of peripheral (finger) temperature

Most of the research on biofeedback induced peripheral temperature control is open to serious methodological and theoretical criticisms. In the present research investigation, increase in peripheral (finger) temperature was targeted because of the possible therapeutic implications for the treatment of migraine and Raynaud's disease. Two experiments are reported in which the pretest-posttest control group design was employed to test the power of the variables in biofeedback induced self-control of finger temperature, and the necessity for subjects to engage in somatic manoeuvres. Significant increases in within-session and absolute finger temperature occurred in a test for self-control only for those subjects who had undergoing contingent feedback-somatic activity training conditions. It is suggested that future research should examine the role of mediational strategies in biofeedback-temperature training.

The peripheral pulse monitor--a review of electrical plethysmography

The electrical plethysmogram, as a monitor of cardiovascular function, is reviewed; and its use as peripheral pulse monitor during clinical anaesthesia is evaluated.

Measurement of anxiety by forearm blood flow

A physiological index of anxiety would be of considerable value if it could evaluate objectively the diminution in anxiety which follows drug treatment, psychotherapy, deconditioning and prefrontal leucotomy. Anxiety is an unpleasant subjective experience of tension, apprehension or anticipation imposed by the expectation of danger or distress or the need for a special effort. The components of the accompanying physiological response lend themselves to objective measurement and are worthy of study since they reflect the emotional changes which defy direct measurement.

FOREARM BLOOD FLOW IN NORMAL SUBJECTS AND PATIENTS WITH PHOBIC ANXIETY STATES

One of the earliest studies on limb blood flow, using a volume plethysmograph to enclose the hand and forearm, was carried out by Hewlett and Van Zwaluwenburg (1909). Two of their patients were pronounced neurasthenics “with labile vasomotor systems” and these authors noted that, excluding subjects with thyrotoxicosis, “the majority of the remaining fast rates occurred in neurasthenics of the vasomotor type”. In 1938 Grant and Pearson, who developed forearm plethysmography to determine blood flow mainly in the skeletal muscle rather than the skin, noted transient increases in forearm flow with mental arithmetic in some subjects, but did not pursue this observation further. This response was studied in more detail by Abramson and Ferris (1940). Their conclusion that mental arithmetic produced an increase in forearm flow due to vasodilatation in the forearm muscles was confirmed by the work of Brod, Fencl, Hejl, and Jirka (1959), who attributed the change to emotional stress.