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O A Smith

Publications and source records attributed to O A Smith.

At least 19 recordsLinked to original sources
PubMed1991

A system to acquire and record physiological and behavioral data remotely from nonhuman primates.

We describe an integrated system to record physiological and behavioral variables from nonhuman primates in social groups. The system records data simultaneously from two animals in family groups of five. It synchronizes behavioral and physiological data within 16 ms, either on-line or from recordings. Behavioral data are entered by trained observers on-line or from videotape. Recordings of physiological data are produced on-line as stripchart records, tape recordings on the audio channels of video cassettes, and magnetic disk files. The physiological data include two arterial blood flows, arterial blood pressure and heart rate. The data are transmitted from freely behaving animals to a central site via radio telemetry. The infrared link controls the radio transmitter and physiological signal processing electronics, as well as two sources of drugs for each animal. All of the electronics are contained in a small, light backpack that can be worn by either male or female baboons.

Animals↗
PubMed1991

Integrating behavior and cardiovascular responses: the code.

The next revolution in biology is predicted to be in the integrative domain, and the need to involve physiologists in this kind of research has been recognized. This paper represents an approach to providing some of the tools required for dealing with integrative physiology at the behavioral level. Video tape recordings are made of the activities of a group of five baboons (Papio hamadryas) while simultaneous recordings of arterial blood pressure, heart rate, renal blood flow, and mesenteric or iliac blood flow are telemetered from two of the members of the group. The telemetered cardiovascular information is recorded on the two audio channels of the videotape. Subsequently the videotape is viewed, and a two-dimensional code is used to record the behavior of the two animals with the telemetry equipment. The first dimension of the code categorizes the behavior changes precisely regarding those aspects of behavior that are related to cardiovascular dynamics and does so with an accuracy of 16 ms. The second dimension codes relevant environmental changes. The paper describes the code and presents illustrations of how the code reflects the cardiovascular dynamics associated with the behavioral changes.

Animals↗
PubMed1990

Neurons controlling cardiovascular responses to emotion are located in lateral hypothalamus-perifornical region.

We did four experiments to determine whether the lateral hypothalamus-perifornical (LH/PF) region is the source of neuronal cell bodies responsible for producing the cardiovascular (CV) responses associated with emotion or the defense reaction. Of particular concern was whether the paraventricular nucleus (PVN) plays a role in the generation of these CV responses. Mapping the hypothalamus with electrical stimulation showed that the CV pattern of responses was never produced by stimulating the PVN and was invariably produced by stimulating the LH/PF region. Complete electrolytic destruction of the PVN and subsequent axonal degeneration did not change the CV pattern of responses elicited by LH/PF stimulation, whereas any encroachment of the lesion on the LH/PF region decreased the magnitude of the CV responses. Injection of the neuroexcitotoxin ibotenic acid (Ibo) into the PVN did not affect responses to LH/PF stimulation, whereas Ibo injection into the LH/PF region eliminated or severely attenuated the CV responses. Retrograde labeling of cells from the thoracic cord and the ventrolateral reticular formation revealed a scattered group of cells in the LH/PF region that may be the cells controlling the CV responses. These results point directly to the LH/PF region as the source of the cell bodies responsible for the autonomic responses associated with emotion or defense reactions.

Animals↗
PubMed1987

Spontaneous hypertension and its sequelae in woolly monkeys (Lagothrix lagotricha).

Arteriolar nephrosclerosis was observed at necropsy in 26 of 38 woolly monkeys (Lagothrix lagotricha). This lesion is the earliest histologic change associated with hypertension in humans. Seventeen of the monkeys had died of congestive heart failure, renal failure or acute cardiovascular accident, complications similar to those seen in human hypertension. All monkeys known to be over 4 years of age were affected. Direct blood pressure measurements in nine otherwise healthy woolly monkeys revealed systolic pressures of 194 +/- 20 mmHg. Our physiologic, clinical and pathologic studies suggest that woolly monkeys develop hypertension spontaneously and could be a useful model for the study of human hypertension.

Animals↗
PubMed1986

Differential effect of behavior on cardiac and vasomotor baroreflex responses.

Bilateral carotid occlusion was performed in seven baboons during dynamic leg exercise, static arm exercise, feeding, rest, and sleep. The baroreceptor reflex effects on blood pressure, heart rate and interval, renal blood flow, and terminal aortic blood flow were determined during each behavior. The carotid sinus baroreflex increase in blood pressure and heart rate was greatest during sleep and least during exercise. The hindlimb and renal vasomotor responses followed different patterns. The baroreceptor reflex sensitivity for renal vasoconstriction was greatest during rest and least during sleep. The reflex sensitivity in the hindlimb was unaltered by behavior. Thus behavior modifies baroreceptor reflex responses in the heart and peripheral circulation in different patterns.

Animals↗
PubMed1984

Organization of central nervous system pathways influencing blood pressure responses during emotional behavior.

A series of studies has demonstrated that the perifornical area of the hypothalamus ("acro-named" HACER, for Hypothalamic Area Controlling Emotional Responses) is responsible for producing the elevated blood pressure and other cardiovascular responses that accompany emotional behavior. The central neural structures providing afferents to the HACER are detailed, and the efferent outflow is analyzed to demonstrate how the HACER produces cardiovascular responses.

Animals↗
PubMed1983

Nerve conduction velocity, microscopic, and electron microscopy studies comparing repaired adult and baby monkey median nerves.

Three to three and a half years after repair of monkey nerves, comparison of total myelinated nerves, electron microscopic sections, and nerve conduction velocities delineated no significant difference between nerves sutured in adult life and those sutured in infancy. Extrapolating these results to the human clinical situation, central nervous system adaption in young patients could explain the better clinical results.

Age Factors↗
PubMed1983

Regional distribution of blood flow during mild dynamic leg exercise in the baboon.

Five chair-restrained baboons were trained with operant techniques and a food reward to perform dynamic leg exercise. Cardiac output and blood flows to most tissues were determined by radioactive microsphere distribution. After 2 min of exercise mean arterial blood pressure had increased by 11 +/- 3% (SE), heart rate by 34 +/- 7%, cardiac output by 50 +/- 12%, and O2 consumption by 157 +/- 17%. The blood flow to exercising leg muscle increased by 585 +/- 338% and to the myocardium by 35 +/- 19%. Blood flow to torso and limb skin fell by 38 +/- 4 and 38 +/- 6%, respectively, and similar reductions occurred in adipose tissue blood flow. Nonworking skeletal muscle blood flow decreased by 30 +/- 10%. Renal blood flow was lowered by 16 +/-2%. The lower visceral organs had more variable responses, but when grouped together total splanchnic blood flow fell by 21 +/- 9%. Blood flow to the brain was unchanged with exercise, whereas spinal cord perfusion increased 23 +/- 3%. Thus during short dynamic exercise baboons redistributed blood flow away from skin, fat, nonworking muscles, and visceral organs to supply the needs of exercising muscles. Our data suggest the baboon is a useful animal model for investigating vascular responses of tissues, such as torso skin, adipose, individual visceral organs, and the spinal cord, that cannot be examined in humans.

Adipose Tissue↗
PubMed1982

Afferent projections to the hypothalamic area controlling emotional responses (HACER).

The Mesulam technique for horseradish peroxidase was used to study the subcortical afferent projections to a location in the hypothalamus that has been shown to control the complete cardiovascular (CV) response accompanying a specific emotional behavior. Major projections common to all baboons injected included the lateral septal nucleus; medial, cortical and basal amygdala; the anteroventral third ventricle area; the preoptic areas; the subiculum; the paraventricular nucleus of the thalamus; periventricular gray and the central gray of the midbrain; the midbrain tegmentum; locus ceruleus, parabrachial and raphe cells in the pons; and in the medulla, raphe nuclei, the nucleus of the solitary tract, in and around the dorsal motor nucleus of the vagus, and in the region of the nucleus ambiguus. Other projections in some but not all baboons included the subfornical organ and the midline and dorsomedial nuclei of the thalamus. The nucleus of the diagonal band of Broca was labeled to some degree with all injections but was most heavily labeled with the injection extending more laterally in the hypothalamus. These results fit well with physiological and behavioral studies dealing with neural control of emotional and CV responses and support the concept of an integrative area in the hypothalamus concerned specifically with the control of CV response accompanying emotion.

Afferent Pathways↗
PubMed1982

[Role of the lateral hypothalamus in the genesis of somato-autonomic responses].

Coagulation of medial and lateral parts of the lateral hypothalamic area increases latency of responses and decreases respiration, arterial blood pressure and heart rate responses to stimulation of the hypothalamic ventromedial nucleus. Coagulation of the perifornical region of the lateral hypothalamus completely eliminates the above autonomic responses. A new rigid integration which is characterized with the increased number of correlated relations between separate components of somato-autonomic responses, was postulated after correlation analysis of somato-autonomic parameters during stimulation of hypothalamic ventromedial nucleus in animals with lateral hypothalamic lesions. The data suggest that somato-autonomic responses to stimulation of negative emotion sites of the hypothalamus are mediated by those brain structures which are under ascending excitatory influences of the lateral hypothalamus.

Animals↗
PubMed1980

Functional analysis of hypothalamic control of the cardiovascular responses accompanying emotional behavior.

The cardiovascular (CV) responses to an acute emotional situation in unanesthetized, chair-restrained baboons include elevations in heart rate, blood pressure, and terminal aortic flow and a complex biphasic reduction in renal flow. The same CV responses can be produced by stimulating an area in the hypothalamus. Furthermore, bilateral ablation of the hypothalamic area eliminates CV responses to the emotional behavior while responses to exercise, free feed, and lever press remain unaltered. This effect is not due to memory loss, loss of emotionality, or a general loss of CV regulatory capacity. Efferent projections of the hypothalamic site were traced by means of autoradiography and afferent sources were traced by horseradish peroxidase injections. Efferents include projections to amygdala, central gray, zona incerta, midline thalamic nuclei, dorsal midbrain tegmentum, the parabrachial region. Afferents were widely distributed and included inputs from the subiculum, amygdala, septal area, central gray, locus ceruleus, interpeduncular nucleus, and bilateral labeling in and around the dorsal motor nucleus of X and the nucleus ambiguus.

Animals↗
PubMed1979

Decreased renal blood flow in the baboon during mild dynamic leg exercise.

Twelve chair-restrained baboons (Papio cynocephalus) were conditioned with operant techniques and a food reward to perform 4 min of dynamic leg exercise. During the last minute of exercise, blood flow through the left renal artery, measured by an electromagnetic flow transducer, was decreased 19 +/- 2% SEM with respect to the minute of rest preceding the exercise. This response occurred within 1.5 min, was maintained throughout the exercise, and recovered to control within 2 min. Mean arterial blood pressure rose 17 +/- 2%; renal vascular resistance, 46 +/- 6%; heart rate, 42 +/- 4%; and whole-body oxygen consumption, 233 +/- 19%. Behavioral situations simulating the arousal and feeding components of the exercise task, but not requiring muscular exertion, did not alter renal blood flow. In four animals, blood flow to the contralateral but surgically denervated kidney was measured; it increased transiently at the onset of exercise, but returned to control by the last minute of work. Thus, the baboon, like man, shows a decrease in renal blood flow during exercise. This response has a rapid onset and recovery and is primarily neurally mediated.

Animals↗
PubMed1979

Effect of implant duration on in vivo sensitivity of electromagnetic flow transducers.

Twenty-three electromagnetic flow transducers with lumen diameters of 3.5-6.0 mm were implanted in rhesus monkeys and baboonss for 12 h to 120 days. Each flow transducer was calibrated 1) in vitro on dialysis tubing with saline before implantation, 2) in vivo the last day of the implant period, and 3) again in vitro after the flow transducer was recovered. Three other flow transducers were implanted on femoral arteries of baboon just central to an arteriovenous Silastic shunt, and were calibrated in vivo daily for 23-47 days. In vitro sensitivity was not affected by implant durations of up to 120 days. In vivo sensitivity fluctuated unpredictably for the first 3-4 wk of implant, after which it followed a systematic course that depended on the lumen size. In vivo sensitivity at any time during implant (after the initial period) could be accurately predicted by knowing either the in vitro sensitivity or the terminal in vivo sensitivity.

Animals↗
PubMed1979

Renal and hindlimb vascular control during acute emotion in the baboon.

Blood pressure, heart rate, oxygen consumption, and blood flow to the renal and hind-limb vasculatures were measured in healthy, unanesthetized baboons (Papio cynocephalus) in a controlled environment. Appropriate behavioral techniques were applied to allow the reproducible elicitation of a conditional emotional response (CER). Section of renal nerves and autonomic pharmacologic interventions were used to determine the mechanisms for the cardiovascular responses accompanying the CER. The resistance changes in the renal and hind-limb vascular beds were generated by rapid, neurally mediated vasoconstriction of the renal vasculature and by a slower acting, circulating vasoactive agent, most probably epinephrine, which causes a delayed second constriction in the renal bed and a net dilation in the hind limbs.

Animals↗
PubMed1976

Sudden death in infant primates from induced laryngeal occlusion.

Thirteen infant and juvenile monkeys and baboons were studied in procedures designed to assess the functional characteristics of the upper airway, with special attention to the consequences of laryngeal nerve stimulation. In young animals, stimulation of the recurrent laryngeal nerve produced closure of the airway in sufficient degree and duration to cause death. Older juvenile monkeys were resistant to fatal laryngospasm induced by nerve stimulation. A variety of patterns of general autonomic response accompanied the airway changes. These results are consistent with (1) a laryngospasm hypothesis to account for certain terminal events in sudden infant death syndrome, and (2) prior observations of age-related general autonomic stability.

Age Factors↗