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Biomedical subjects

J Sugenoya

Publications and source records attributed to J Sugenoya.

At least 19 recordsLinked to original sources
PubMed1998

Vasodilator component in sympathetic nerve activity destined for the skin of the dorsal foot of mildly heated humans.

1. Skin sympathetic nerve activity (SSNA) was recorded in seven male subjects from the peroneal nerve by microneurography, and the temporal correspondence of spontaneously occurring SSNA bursts with vasodilatation and sweating responses on the dorsal foot was studied during a mild body heating at rest. 2. Some SSNA bursts were followed by a sweat expulsion with a latency of 2.4 +/- 0.4 s, and some bursts by a transient vasodilatation with a latency of 2.2 +/- 0.4 s (means +/- S.D.). SSNA bursts followed both by a sweat expulsion and by a vasodilatation response (Type 1), those followed only by a sweat expulsion (Type 2) and those followed only by a vasodilatation, response (Type 3) were 70%, 10% and 1% of the total bursts examined, respectively. 3. For Type 1 bursts, there was a significant, but weak linear relationship among the burst amplitude, the amplitude of the corresponding vasodilatation and the amplitude of the corresponding sweat expulsion. 4. It was concluded that SSNA contains vasodilatory activity which is synchronous with sudomotor nerve activity. The results suggest that such vasodilatory activity contributes to sustaining the sweat gland function by supplying sufficient blood.

Adult↗
PubMed1997

Altered response in cutaneous sympathetic outflow to mental and thermal stimuli in primary palmoplantar hyperhidrosis.

Skin sympathetic nerve activities (SSNAs) were recorded simultaneously from the tibial and peroneal nerves by microneurography at an ambient temperature of 25 degrees C in five subjects with primary palmoplantar hyperhidrosis. The resting of the tibial SSNA innervating the sole (glabrous skin) increased moderately (36.5 +/- 1.5 bursts/min), while mental arithmetic provoked marked responses (1,003.3 +/- 457.4% compared with the resting level) in the hyperhidrosis group compared with the control normohidrosis group (n = 5, 25.3 +/ 4.2 bursts/min and 142.2 +/- 58.4%, respectively). Differentiation of the tibial SSNA into sudomotor (innervating sweat glands) and vasoconstrictor (innervating presphincter of skin vessels) revealed that this SSNA enhancement was attributable to not only sudomotor but also vasoconstrictor components during mental arithmetic. In contrast, the responses in the peroneal SSNA (innervating the dorsum pedis, hairy skin) of the hyperhidrosis group were only slightly changed, exhibiting no significant difference from those in the normohidrosis group. Reflex bursts elicited by sound and electric stimulation were normal in amplitude and latency. When the ambient temperature was elevated to 30 degrees C, the tibial SSNAs became more enhanced than did the peroneal SSNAs. The tibial SSNA was markedly enhanced in the hyperhidrosis group (290.0 +/- 78.5%) compared with the normohidrosis group (78.3 +/- 25.4%). We conclude that the excessive responses in SSNA to the plantar glabrous skin to both mental and thermal stimuli may be responsible for the profuse sweating in subjects with primary palmoplantar hyperhidrosis.

Acoustic Stimulation↗
PubMed1997

Impairment of calcitonin gene-related peptide-induced potentiation of cholinergic sweat secretion in patients with multiple system atrophy.

Loss of sweating is a characteristic feature of multiple system atrophy (MSA) with autonomic failure, and widespread anhidrosis may lead to hyperthermia and collapse in a hot environment. Calcitonin gene-related peptide (CGRP) is present in the periglandular nerves around sweat glands and is a strong stimulant of methacholine (MCH)-mediated cholinergic sweating. The present study evaluated CGRP-related regulation of cholinergic sweating in patients with MSA. CGRP-induced potentiation of MCH-mediated cholinergic sweating was significantly reduced in MSA patients as compared with normal age-matched controls. These results suggest that regulation of sweating is extensively affected in MSA as a consequence of peptidergic dysfunction.

Autonomic Nervous System Diseases↗
PubMed1995

Cutaneous vasodilatation responses synchronize with sweat expulsions.

To examine whether cutaneous active vasodilatation is mediated by sudomotor nerve fibres we recorded cutaneous blood flow and sweat rates continuously with laser-Doppler flowmetry and capacitance hygrometry, respectively, from the dorsal and plantar aspects of the foot in 11 male subjects at varying ambient temperatures (Ta) between 22 and 40 degrees C (relative humidity 40%). In a warmer environment (Ta 29-40 degrees C), predominant responses of the blood flow curve from the sole of the foot were transient depressions (negative blood flow responses, NBR), whereas those from the dorsal foot were transient increases (positive blood flow responses, PBR). The PBR on the dorsal foot occurred spontaneously or in response to mental or sensory stimuli, and when PBR did not fuse with each other the rate of PBR was linearly related to tympanic temperature. When dorsal foot sweating was continuous, PBR on the dorsal foot almost entirely synchronized with sweat expulsion. When dorsal foot sweating was intermittent PBR sometimes occurred on the dorsal foot without corresponding sweat expulsions, but these PBR showed a complete correspondence with subthreshold sweat expulsion seen on a methacholine-treated area. The amplitude and the duration of PBR showed a significant linear relationship with the amplitude and the duration of the corresponding sweat expulsion. In a thermoneutral or cooler environment (Ta 22-29 degrees C), PBR occurred on the sole of the foot when mental or sensory stimuli elicited sweating in that area. Thus, PBR occurred when and where sweating appeared. Atropine failed to abolish PBR on the dorsal foot. Blockade of the peroneal nerve eliminated both PBR and NBR on the dorsal foot.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Different thermal dependency of cutaneous sympathetic outflow to glabrous and hairy skin in humans.

We investigated the effects of ambient temperature on the sudomotor and vasoconstrictor components of skin sympathetic nerve activity (SSNA). The sympathetic traffic was measured by simultaneous microneurographic recording from post-ganglionic nerve fibres in the tibial and the peroneal nerves. When the ambient temperature was raised from 25 degrees C to 34 degrees C, both sudomotor and vasoconstrictor components of SSNA were enhanced in the peroneal nerve but were suppressed in the tibial nerve. The sudomotor and vasoconstrictor sympathetic outflows were elevated in both nerves when the temperature was lowered from 34 degrees C to 18 degrees C. Our results suggested that the sudomotor and the vasoconstrictor components of SSNA are differently modulated by ambient temperature. The difference in sudomotor and vasoconstrictor components of SSNA in the tibial and the peroneal nerves at different ambient temperature may have been responsible for the differences observed in sweating and vasoconstriction in glabrous and hairy skin.

Adult↗
PubMed1993

Effects of body and head positions on bilateral difference in tympanic temperatures.

We have examined the nonparallel changes in tympanic membrane temperatures (Tty) from the two ears in response to various changes in body and head positions. Upon assuming a lateral recumbent position, the Tty on the lower side increased while that on the upper side decreased. Pressure application over a wide area of the lateral chest only caused inconsistent and obscure asymmetric changes in Tty. A lateral flexion of the head with the subject sitting upright and a rotation of the head to the side in a supine position induced an increase in the Tty on the lower side compared to that on the upper side. The temperature and blood flow of the forehead often decreased on the lower side and increased on the upper side, although such responses were not always concomitant with the asymmetric changes in Tty. A dorsal flexion of the head with the subject in a reclining position caused a slight increase in the Tty, whereas raising the head upright induced a slight decrease in them. Two additional experiments were carried out with single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime as tracer, and a slight, relative decrease in counts was noted in the right hemisphere during rotation of the head to the right. These results would strongly suggest that unilateral increases and decreases in Tty could have been caused by one-sided decreases and increases, respectively, in blood flow to the brain and/or the tympanic membrane, induced by a vasomotor reflex involving vestibular stimulation.

Adult↗
PubMed1992

Preferred ambient temperature for old and young men in summer and winter.

To investigate the effects of age on thermal sensitivity, preferred ambient temperature (Tpref) was compared between old (71-76 years) and young (21-30 years) groups, each consisting of six male subjects in summer and winter. The air temperature (Ta) was set at either 20 degrees C or 40 degrees C at commencement. The subject was directed to adjust the Ta for 45 min by manipulating a remote control switch to the level at which he felt most comfortable. In the older group, the Tpref was significantly lower in trails starting at 20 degrees C than that starting at 40 degrees C in summer. The fluctuation of Tpref (temperature difference between maximum and minimum Ta during the last 10 min) was significantly wider in the older group in both summer and winter. Repetition of the same experiment on each subject showed a poorer reproducibility of Tpref in the older group than in the younger group in summer. Tympanic and esophageal temperatures of the older group kept falling throughout the trial starting at 20 degrees C in summer. These results suggest that thermal sensitivity is decreased with advancing age and that thermal perception in the elderly, especially to cold, is less sensitive in summer.

Acclimatization↗
PubMed1992

[Laser-Doppler flowmetry].

Laser-Doppler flowmetry (LDF) is a non-invasive technique for measuring the tissue blood flow. It has been shown in the skin that LDF discloses blood flow fluctuations due to vasomotor nerve activity. LDF can give measurements of blood flow at various sites of different tissue. Furthermore, LDF may enable selective measurement of blood flow at different depths within the tissue, when the device and the probe are appropriately chosen. Thus, LDF is available for examining vasomotor responses at various tissue sites. For clinical application, a method for calibrating the LDF signal in absolute units should be established.

Autonomic Nervous System Diseases↗
PubMed1991

Dynamic sweating response of man to infrared irradiation in various spectral regions.

In an attempt to detect differences in the thermal effect of infrared irradiation of different wave-lengths, transient sweating response to infrared irradiation in various spectral regions was examined. In Series 1, the ventral or dorsal surface of the nude subject was irradiated repetitively for a period of 4 min (2 min on, 2 min off) by each of three kinds of infrared heaters with main emissivity in 'near-infrared' (NIR; 0.7-2.8 microns), 'intermediate-infrared' (MIR; 1.5-5.8 microns), and 'far-infrared' (FIR; 2.8-25 microns) regions. The sweating response on a non-irradiated area tended to be the greatest with MIR, while the magnitude of the sweating response on the irradiated area showed no consistent differences among various wavelengths. The results infer that MIR stimulated cutaneous thomoreceptors most effectively, while its direct effect on local sweat gland activity was minimal. In Series 2, the effects of 9-12 min irradiations in more restricted ranges of wavelength were compared by the combination of the three kinds of heaters with filters (translucent to wavelength ranges of 1.3-2.7, 2.7-3.5, 3.6-8.0 microns, respectively). The sweating response on a remote area was predominantly greater with the range of 2.7-3.5 microns than with the other wavelength ranges, while the local effect on sweating was minimal with this range. The results of Series 2 reinforce those of Series 1, indicating that the degree of stimulation of cutaneous thermoreceptors and of direct thermal effect on sweat gland activity differ with spectral regions incident on the skin, thus affecting local and remote effects on the sweating response.

Adolescent↗
PubMed1991

The assessment of sudomotor dysfunction in multiple system atrophy.

We studied sudomotor function in 21 patients with multiple system atrophy and in 11 age-matched controls. The extent and severity of the sudomotor deficit was assessed using the quantitative thermoregulatory sweat test. Central sudomotor function was studied by measuring sweating in response to raising body heat and administering thyrotropin-releasing hormone. Postganglionic sudomotor function was studied using the sudomotor axon reflex test evoked by nicotine. We conclude that in multiple system atrophy, thermoregulatory sudomotor dysfunction was more severe in the lower extremities. Heat stimulation increased the frequency of sweat expulsion and sweat rate on the forearm in moderate multiple system atrophy to a similar degree as controls but failed to do so on the thigh. Thyrotropin-releasing hormone enhanced sweating in moderate multiple system atrophy and controls. Results of the sudomotor axon reflex test indicate that in multiple system atrophy there is postganglionic sudomotor dysfunction which may be due to transsynaptic changes. These results suggest that the main lesion responsible for sudomotor dysfunction in multiple system atrophy is within the intermediolateral column cells of the spinal cord.

Adult↗
PubMed1990

Identification of sudomotor activity in cutaneous sympathetic nerves using sweat expulsion as the effector response.

In a warm environment at ambient temperatures between 25 degrees and 38 degrees C (relative humidity 50%-60%) the relationship between sympathetic activity in cutaneous nerves (SSA) and pulses of sweat expulsion was investigated in five young male subjects. The SSA was recorded from the peroneal nerve using a micro-electrode. Sweat expulsion was identified on the sweat rate records obtained from skin areas on the dorsal side of the foot, for spontaneous sweating and drug-induced sweating, using capacitance hygrometry. Sweat expulsion was always preceded by bursts of SSA with latencies of 2.4-3.0 s. This temporal relationship between bursts of SSA and sweat expulsion was noted not only in various degrees of thermal sweating but also in the sweating evoked by arousal stimuli, or by painful electric stimulation. The amplitude of the sudomotor burst was linearly related to the maximal rate of increase of the corresponding sweat expulsion, the amplitude of the expulsion and the integrated amount of sweat produced for the duration of the expulsion. The results provide direct evidence that sweat expulsion reflects directly centrally-derived sudomotor activity.

Adult↗
PubMed1988

Effects of thyrotropin releasing hormone on human sudomotor and cutaneous vasomotor activities.

At an ambient temperature of 34-41 degrees C (rh = 40%) forearm sweat rates were measured by capacitance hygrometry in 9 male volunteers. Thyrotropin releasing hormone (TRH) was infused intravenously at 0.1 mg.min-1 for 20 to 30 min. Sweat rate increased rapidly within a minute after initiation of TRH infusion, decreased rapidly after the peak sweat rate was attained in 2-5 min of TRH infusion, and then levelled off in 6-10 min near the level before TRH infusion. Core temperature (Tre, Tty) started to decline at the time of the peak sweat rate and levelled off almost coincidentally with the levelling off in sweat rate. Average values for the rate of sweat expulsions (Fsw), sweat rate and mean body temperature (Tb) were obtained from the data of the last 10 min period of TRH infusion. The regression line for the relationship of Fsw to Tb shifted during the TRH infusion to the left of the line for the control; that of sweat rate to Fsw hardly shifted. At an ambient temperature of 24-27 degrees C TRH produced vasodilation as evidenced by an increase in skin blood flow (measured by means of thermal distribution), an increase in amplitude of the photoelectric plethysmogram and an elevation of skin temperature in the finger tips. It is suggested that TRH may act, either directly or indirectly, on the central thermoregulatory mechanism (or on the thermoreceptive mechanism) to lower the reference temperature for heat dissipation.

Adult↗
PubMed1988

Effect of facial cooling during heat acclimation process on adaptive changes in sweating activity.

On assumptions that tympanic temperature (Tty) reflects brain temperature and that the latter can be lowered by cooling of the face, effect of facial cooling during acclimation process on adaptive changes in sweating activity was examined, in comparison with the results of our previous studies on heat acclimation with controlled hyperthermia. Face fanning, by which Tty was clamped at approximately 37.1 degrees C, was combined with either of the following 9-day acclimation procedures: 90-min heating in a "Sauna box," keeping mean skin temperature slightly above 40 C, or 90-min exercise on a bicycle, clamping rectal temperature (Tre) at approximately 38 degrees C. Each procedure was imposed on the same four male subjects on different occasions, two of whom had participated in our previous experiments. Sweat tests, carried out before and immediately after the completion of the procedure, consisted of measurements of local sweat rates, whole body sweat rate, Tre, Tty, and skin temperatures on 5 areas, and of calculations of mean body temperature (Tb) and the rate of sweat expulsions (Fsw, as an indicator of central sudomotor activity). No or only a slight increase in sweating activity was observed following the acclimation procedures with face fanning, whereas similar procedures without face fanning had resulted in substantial enhancement of sweating activity in most of the cases, which had been attributed mainly to adaptive changes in central sudomotor activity (as indicated by a shift of the regression line relating Fsw to Tb). Similar results were obtained in an additional series of experiments, where the effects of 9-day 90-min exercise in heat, clamping Tre at approximately 38.2 degrees C, with and without facial cooling, were compared with each other in a subject. From the above results it is inferred that Tty reflects brain temperature and that enhancement of sweating activity induced by repeated heat load is strongly impeded, if not accompanied, by an elevation of brain temperature.

Acclimatization↗
PubMed1987

Local effect of vasoactive intestinal polypeptide on human sweat-gland function.

Physiological significance of vasoactive intestinal polypeptide (VIP), a putative co-transmitter of the cholinergic neuron innervating sweat glands, was investigated by its local effect on drug-induced sweating. VIP, methacholine chloride (MCH), or VIP plus MCH dissolved in 0.1 ml of 0.9% NaCl solution to a specified concentration was injected intradermally at the center of a forearm test area of 15 cm2 and the sweat rate was recorded continuously by capacitance hygrometry. In a cool environment (Ta, 23 degrees C), VIP failed to cause sweat secretion, but increased the rate of MCH-induced sweating, most markedly at a concentration of 10(-5) g/ml, where the rise in local skin temperature was the greatest. On an area anesthetized by nerve block in a hot environment (Ta, 35 degrees C), the effect was less obvious and less consistent, indicating that the sweat-facilitatory effect of VIP is reduced under the condition of passive cutaneous vasodilation. It may be postulated that VIP plays a role in securing ample oxygen supply to functioning sweat glands, especially with a relatively high cutaneous vasoconstrictor tone.

Adult↗
PubMed1985

Characteristics of central sudomotor mechanism estimated by frequency of sweat expulsions.

Each of six male subjects was exposed during rest to at least ten different thermal environments (Ta, 22-44 degrees C; rh, 40%). Local sweat rates from both forearms were continuously recorded in a steady state of each exposure, using capacitance hygrometry. In the absence of spontaneous sweating, localized sweating was induced by intradermal administration of pilocarpine. Sweat expulsions synchronous at the two test areas were counted and their frequency (Fsw) was calculated. For each of additive and multiplicative combinations of Tcore (Tre, Tty) and Ts, the best combination for estimation of thermal input to the sudomotor center was determined using multiple regression analysis. Approximately 0.75Tre + 0.25Ts or 0.85Tty + 0.15Ts, and (Tre-36.33) (Ts-33.13) or (Tty-36.42) (Ts-32.24) were obtained for the additive and multiplicative combinations, respectively. The correlation coefficient (r) for the relationship of Fsw to the obtained best combination, either additive or multiplicative, and that of Fsw to Tb were almost comparable to each other. It is considered that Tb can be used as an approximation of thermal input and that the characteristics of frequency of sweat expulsion is a useful index for determining whether and how much the central sudomotor mechanism is involved in the change of sweat rate in response to various thermal and non-thermal stresses.

Adult↗
PubMed1982

Occurrence of mental and thermal sweating on the human axilla.

Sweat responses to mental arithmetic were recorded simultaneously on the axilla, palm, and general body surface (chest and forearm) by resistance or capacitance hygrometry at different ambient temperatures. Sweat expulsions observed on the axilla were fully synchronized with those on the general body surface, but not always with those on the palm. In some subjects the sweat responses to mental arithmetic on the general body surface were different in pattern from those on the palm. In such subjects the sweat response pattern on the axilla was similar to that on the general body surface. The sweat response to mental arithmetic occurred at a considerably lower environmental temperature on the axilla than on the general body surface. The occurrence of the sweat response on the axilla can be related to the peculiar feature of axillary thermal sweating: a lower threshold temperature and less responsiveness to thermal load compared with thermal sweating on the general body surface. This suggests that mental sweating on the axilla occurs due to the characteristic feature of thermal sweating on the axilla. Axillary eccrine sweating is not different qualitatively from sweating on the general body surface.

Adult↗