A neuropathic deficit, decreased sweating, is prevented and ameliorated by euglycemia in streptozocin diabetes in rats

Decreased sweating, especially of feet and legs, occurs in human diabetic neuropathy. It might be studied in experimental diabetes to characterize it, elucidate its mechanisms, and determine whether it can be prevented or treated. The pilocarpine-induced sweat responses (SR) in the hind foot pads of groups of control and streptozocin diabetic rats, in good (GC) and in poor (PC) glycemic control and with a crossover design after 20 wk of diabetes, were evaluated with the silicone mold sweat test to determine the number of sweat droplets per group of foot pads. The SR was dose dependent and reproducible. The SR disappeared with denervation and reappeared with reinnervation; denervation hypersensitivity did not develop. In the GC group, euglycemia was achieved by regulating the caloric intake and using multiple daily injections of Ultralente insulin. The SR was not different from that of the control group for up to 136 d. In the PC group, the SR became abnormal (P less than 0.005) at 16 d and progressively worsened: 40% of baseline values at 14 wk (P less than 0.001). After restoring euglycemia in the PC group, a normal SR occurred at 12 d. These results show that one human neuropathic deficit, failure of sweating, can be prevented or ameliorated by good glycemic control.

Functional and morphological changes in the eccrine sweat gland with heat acclimation

Three adult male patas monkeys (11-15 kg) were heat acclimated by continuous exposure to an ambient temperature of 33 +/- 1 degree C at 13% relative humidity for 9 mo. During the last month, they were also exposed to 45 degrees C at 10% relative humidity for 4 h/day and 5 days/wk. Before and after 3 wk of acclimation, the animals were given a heat-tolerance test in which rectal (Tre) and mean skin (Tsk) temperatures, heart rate, and sweat rate (msw) were monitored during a 90-min exposure to 45 degrees C heat with 24% relative humidity under lenperone (1.0-1.4 mg/kg im) tranquilization. Maximal in vivo msw was also determined in response to subcutaneous injections (1 and 10% solutions) of methacholine (MCh). Before and after 9 wk and 9 mo of acclimation, sweat glands were dissected from biopsy specimens of the lateral calf, cannulated, and stimulated in vitro with MCh. Morphological measurements of isolated tubules were compared with maximal secretory rates produced by MCh stimulation. Three weeks of acclimation 1) reduced Tre and Tsk and increased msw during the heat tolerance test and 2) significantly increased maximal msw in response to MCh stimulation. Acclimation also increased (P less than 0.05) sweat gland size, as measured by tubular length and tubular volume. Maximal in vitro msw produced by MCh stimulation and msw per unit length of secretory coil also increased significantly. We conclude that heat acclimation increases the size of eccrine sweat glands and that these larger glands produce more sweat. They are also more efficient because they produce more sweat per unit length of secretory coil.

Effects of caffeine ingestion on body fluid balance and thermoregulation during exercise

This study investigated the effects of caffeine supplementation on thermoregulation and body fluid balance during prolonged exercise in a thermoneutral environment (25 degrees C, 50% RH). Seven trained male subjects exercised on a treadmill at an intensity of 70-75% of maximal oxygen consumption to self-determined exhaustion. Subjects exercised once after caffeine and once after placebo ingestion, given in a double-blind crossover design. Five milligrams per kilogram body weight of caffeine followed by 2.5 mg.kg-1 of caffeine were given 2 and 0.5 h before exercise, respectively. Rectal temperature was recorded and venous blood samples were withdrawn every 15 min. Water loss and sweat rate were calculated from the difference between pre- and post-exercise body weight, corrected for liquid intake. Following caffeine ingestion, when compared with placebo, no significant difference in final temperature or in percent change in plasma volume were found. No significant differences were observed in total water loss (1376 +/- 154 vs. 1141 +/- 158 mL, respectively), sweat rate (12.4 +/- 1.1 vs. 10.9 +/- 0.7 g.m-2.min-1, respectively), rise in rectal temperature (2.1 +/- 0.3 vs. 1.5 +/- 0.4 degrees C, respectively), nor in the calculated rate of heat storage during exercise (134.4 +/- 17.7 vs. 93.5 +/- 22.5 W, respectively). Thus, in spite of the expected rise in oxygen uptake, caffeine ingestion under the conditions of this study does not seem to disturb body fluid balance or affect thermoregulation during exercise performance.

Scopolamine withdrawal syndrome

As travel by air and ship becomes increasingly popular, more and more travelers are using transdermal scopolamine to avoid motion sickness. In fact, it has become almost fashionable for ocean travelers to sit on the sun deck with a patch behind the ear. This article describes withdrawal symptoms in a patient who used transdermal scopolamine beyond the recommended 3 days.

Atropine-induced cutaneous vasodilation decreases esophageal temperature during exercise

Four healthy adult males volunteered for this study, which followed informed-consent procedures administered by our local Human Use Committee. Esophageal (Tes) and mean skin (Tsk, eight site) temperatures, forearm sweating rate (ms), metabolism (M), heart rate (HR), and forearm blood flow (FBF) were measured at rest and during forearm blood flow (FBF) were measured at rest and during exercise [55% oxygen consumption (Vo2) peak] during control experiments and after 2 mg im atropine (ATR). Experiments were randomized and separated by at least 72 h. ATR increased heart rate at rest by 15 beats/min and during exercise by 24 beats/min. ATR decreased whole body sweating by 57%. All eight local skin temperatures were higher in ATR than in control. Tsk was 32.6 degrees C in ATR and 31.0 degrees C in control (P less than 0.01). During exercise, ATR increased vasodilation of the forearm compared with control. The slope of FBF to Tes increased over 300% in ATR experiments compared with control (P less than 0.05). The higher sensible heat flux from this vasodilation decreased Tes during exercise, which further decreased sweating. Skin blood flow remained elevated as Tes decreased, suggesting that local vasodilatory factors promoted atropine-induced cutaneous vasodilation.

The effect of nicardipine, a calcium channel blocker, on the sweat test in adult patients with cystic fibrosis

Impaired cell membrane chloride ion movement in cystic fibrosis results in reduced resorption of sodium and chloride from sweat gland ductules producing the high concentrations measured in the sweat as a diagnostic test. Normal chloride ion movement can be restored in vitro by blocking transepithelial calcium flux with lanthanum, suggesting a potential role for calcium channel blocking drugs in the management of cystic fibrosis. We studied the effect of nicardipine, a calcium channel blocker, on the sweat sodium in 17 adult patients with cystic fibrosis. Nicardipine was administered intravenously or topically using iontophoresis or occlusive dressing. No significant change in sweat sodium concentration was observed between pre- and post-drug administration. We conclude that nicardipine used in vivo does not exert the same effect as lanthanum demonstrates in vitro on transepithelial cell membrane chloride ion movement in cystic fibrosis.

Sweating patterns in atopic dermatitis patients

Postganglionic sweat output in ten patients with atopic dermatitis was determined by a quantitative sudomotor axon reflex test in which the output results from axon reflex stimulation by acetylcholine iontophoresis. All measurements were obtained from normal skin on the volar aspect of the left wrist and dorsal aspect of the left foot of the atopic patients. Latency, sweat volume, and dynamic sweat pattern were variables included in the study. An abnormal value or configuration was found in nine of the ten patients studied. Seven of the ten patients had abnormal sweat output values. Atopic patients have abnormal sweating patterns, which may be inherently responsible for or related to their disorder.

Antiperspirant activity of H1-histamine blockers as determined by a modified rat foot pad assay

A method for inducing sweating in the rat via heat stress and without the use of general anesthetics is presented. Five commonly used H1-blocking antihistamines were evaluated in this model for their antiperspirant efficacy. The antihistamines evaluated and their ED50 values (micrograms base/pad) were as follows: phenindamine, 3.02; diphenhydramine, 3.25; chlorpheniramine, 3.12; tripelennamine, 4.91; and pyrilamine, 13.03. Atropine sulfate, injected into the foot pads, was also found to inhibit the sweat response. The response to atropine varied directly with dose. The ED50 was estimated to be 0.4 ng base/foot pad. No systemic effects or contralateral involvement were seen. The rat foot pad contains eccrine sweat glands that are innervated by sympathetic cholinergic fibers. This relationship is analogous to that in the eccrine sweat glands of man. The rat data suggest that antihistamines, possibly via an anticholinergic effect, may be useful as potential antiperspirants in man.

Effects of CSF ANG II and AVP on sweating in the heat-stressed patas monkey

Increasing cerebrospinal fluid [Na+] reduces sweat rate (msw) in the heat-stressed patas monkey (Erythrocebus patas). This study determined the potential role of two neuropeptides, angiotensin II (ANG II) and arginine vasopressin (AVP), in mediating this response. Artificial cerebrospinal fluid, containing either ANG II or AVP, was infused into the third cerebral ventricle of lenperone-tranquilized monkeys (n = 4) exposed to 41 +/- 2 degrees C. Solutions were infused at 16.5 microliters/min for 25 min (total vol approximately 413 microliters). ANG II (1.25, 2.5, 5, and 10 ng/microliters) tended to decrease .msw. However, during infusion, only the decline at 10 min associated with the 1.25-ng/microliters dose (26%) was different (P less than 0.004) from control. This dose elevated (P less than 0.004) core rectal temperature by 1.14 degrees C at 20 min postinfusion. In contrast, AVP (0.5 and 1.5 micrograms/microliters artificial cerebrospinal fluid) had no significant effect on .msw compared with control infusions. Both doses of AVP produced a slight but significant increase in rectal temperature of 0.14 and 0.22 degrees C, respectively, at 20 min postinfusion. In conclusion, the magnitude and time course of the change in .msw with central ANG II suggest that it does not act as the sole mediator of the decline in .msw observed with elevated cerebrospinal fluid [Na+]. The minimal effects produced by third ventricular AVP exclude this route as a means by which AVP could modulate .msw during dehydration.

Transepidermal water loss with and without sweat gland inactivation

The influence of eccrine sweating on transepidermal water loss (TEWL) was investigated. TEWL was simultaneously measured on both forearms, with and without topical inactivation of the eccrine sweat glands by 0.3 ml of 0.5% aqueous scopolamine hydrobromide (HBr), applied under 1 h occlusive patches. The degree of sweat inhibition, after exercise, was measured at 2, 3 and 4 h after patch removal. In 42 out of 44 subjects, complete sweat inhibition (on exercise) was achieved only at 4 h after removal. After a 15-min rest in a room at 20 degrees C, the pre-exercise TEWL values (at 4 h) on the treated and untreated sites were not different (P greater than 0.05), in 38 out of 44 subjects. By this rest period, sweating due to slight physical, thermal or even emotional stimuli may be prevented in most subjects. In the other 6 subjects, the pre-exercise TEWL values (at 4 h) on the untreated site were 1-1.8 g/m2h higher than (P less than 0.001) on the treated site, due to emotional sweating. Thus, accurate baseline TEWL measurements may only be made after anticholinergic suppression of the sweat glands. In this way, accurate TEWL measurements may be made even outside favourable laboratory conditions, at industrial sites etc., where circumstances are far from ideal. The effect of this agent applied to a skin site previously irritated artificially by a 24-h occlusive sodium lauryl sulphate (SLS, 0.3 ml, 0.5% aq.) patch, was also investigated in 17 subjects. In all subjects, 4 h after removal, sweating (on exercise) was completely inhibited on the scopolamine-treated site, pre-irritated with SLS.(ABSTRACT TRUNCATED AT 250 WORDS)

Sweat gland reinnervation by sudomotor regeneration after different types of lesions and graft repairs

Clinical and experimental investigations have shown that recovery of motor and sensory functions after a nerve lesion varies with the type of lesion and the repair technique. We report a study on regeneration of sudomotor axons to sweat glands (SGs) in the mouse paw following different sciatic nerve injury procedures: freezing, crushing, and sectioning. After sectioning, repair was by primary suture or by grafting with the resected section or with conduits of plastic or collagen. Successful regeneration was marked by the reappearance of SG reactivity to pilocarpine. After a freezing or crushing lesion, SGs activated by pilocarpine reappeared by 17 days postoperation and then increased progressively in number until the preoperative number of SGs were again active at 41 days. Cutting the nerve followed by primary repair resulted in a short delay and a significant deficiency in reinnervation. Results obtained with a graft of a segment of resected nerve were similar to primary repair after nerve section and better than when grafts of plastic or collagen tubes were used. This suggests that substances provided by the grafted nerve segment and the type of conduit provided play important roles in the regeneration of unmyelinated axons.

Stimulated eccrine gland function in primary Sjögren's syndrome

Sweat secretion rate, stimulated by iontophoresis of pilocarpine, was measured in 22 patients with primary Sjögren's syndrome and 22 age- and sex-matched normal control subjects. There was no significant difference in measured sweat rates (P = 0.45). We conclude that the complaint of dryness of the skin in patients with Sjögren's syndrome is not due to decreased eccrine gland secretion.

Effects of fluid, electrolyte and substrate ingestion on endurance capacity

The availability of carbohydrate (CHO) as a substrate for the exercising muscles is known to be a limiting factor in the performance of prolonged cycle exercise, and provision of exogenous CHO in the form of glucose can increase endurance capacity. The present study examined the effects of ingestion of fluids and of CHO in different forms on exercise performance. Six male volunteers exercised to exhaustion on a cycle ergometer at a workload which required approximately 70% of Vo2max. After one preliminary trial, subjects performed this exercise test on six occasions, one week apart. Immediately before exercise, and at 10-min intervals throughout, subjects ingested 100 ml of one of the following: control (no drink), water, glucose syrup, fructose syrup, glucose-fructose syrup or a dilute glucose-electrolyte solution. Each of the syrup solutions contained approximately 36 g CHO per 100 ml; the isotonic glucose-electrolyte solution contained 4 g glucose per 100 ml. A randomised Latin square order of administration of trials was employed. Expired air samples for determination of Vo2, respiratory exchange ratio and rate of CHO oxidation were collected at 15-min intervals. Venous blood samples were obtained before and after exercise. Subjects drinking the isotonic glucose-electrolyte solution exercised longer (90.8 (12.4) min, mean (SEM] than on the control test (70.2 (8.3) min; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Antiperspirants and deodorants--ingredients and evaluation]

Antitranspirants and deodorants gain more and more interest. Aluminium chlorohydrate and aluminium zirkonium tetrachlorohydrate glycine complex are the most frequently used active ingredients in commercial antitranspirants today. Aluminium chloride and propantheline bromide, the anticholinergic substance, are important alternatives although less common. Active ingredients of deodorants are mainly perfumes or bactericidal/bacteriostatic substances, such as triclosan. In addition, there are substances which are meant to bind offending smells (e.g. zinc ricinoleate) or to influence the skin surface pH (e.g. triethyl citrate). As in the cosmetics industry in general, both safety and efficacy of a product are major parameters in the experimental and clinical evaluation. Establishment of efficacy is based on olfactory tests in model situations as well as on the detection of associated effects (e.g. influence on cutaneous microflora).

Seasonal variation in responsiveness of human eccrine sweat glands to phenylephrine

The responses of eccrine sweat glands to intradermally injected phenylephrine were studied in six healthy male volunteers in two experiments carried out in February and June. Phenylephrine (10(-7)-10(-2) M, 50 microliters) had no consistent effect on sweat gland activity during February, but evoked dose-related increases in sweat gland activity during June. Responsiveness to phenylephrine could be antagonized by prazosin (10(-5) and 10(-4) M) added to the injection solution.

Developmental interactions between sweat glands and the sympathetic neurons which innervate them: effects of delayed innervation on neurotransmitter plasticity and gland maturation

The neurotransmitter properties of the sympathetic innervation of sweat glands in rat footpads have previously been shown to undergo a striking change during development. When axons first reach the developing glands, they contain catecholamine histofluorescence and immunoreactivity for catecholamine synthetic enzymes. As the glands and their innervation mature, catecholamines disappear and cholinergic and peptidergic properties appear. Final maturation of the sweat glands, assayed by secretory competence, is correlated temporally with the development of cholinergic function in the innervation. To determine if the neurotransmitter phenotype of sympathetic neurons developing in vivo is plastic, if sympathetic targets can play a role in determining neurotransmitter properties of the neurons which innervate them, and if gland maturation is dependent upon its innervation, the normal developmental interaction between sweat glands and their innervation was disrupted. This was accomplished by a single injection of 6-hydroxy-dopamine (6-OHDA) on Postnatal Day 2. Following this treatment, the arrival of noradrenergic sympathetic axons at the developing glands was delayed 7 to 10 days. Like the gland innervation of normal rats, the axons which innervated the sweat glands of 6-OHDA-treated animals acquired cholinergic function and their expression of endogenous catecholamines declined. The change in neurotransmitter properties, however, occurred later in development than in untreated animals and was not always complete. Even in adult animals, some fibers continued to express endogenous catecholamines and many nerve terminals contained a small proportion of small granular vesicles after permanganate fixation. The gland innervation in the 6-OHDA-treated animals also differed from that of normal rats in that immunoreactivity for VIP was not expressed in the majority of glands. It seems likely that following treatment with 6-OHDA sweat glands were innervated both by neurons that would normally have done so and by neurons that would normally have innervated other, noradrenergic targets in the footpads, such as blood vessels. Contact with sweat glands, therefore, appears to suppress noradrenergic function and induce cholinergic function not only in the neurons which normally innervate the glands but also in neurons which ordinarily innervate other targets. Effects of delayed innervation were also observed on target development. The appearance of sensitivity to cholinergic agonists by the sweat glands was coupled with the onset of cholinergic transmission.(ABSTRACT TRUNCATED AT 400 WORDS)

Cluster headache: forehead sweating pattern during heating and pilocarpine tests. Variation as a function of time

Thirty-one patients with cluster headache were examined with regard to their forehead sweating pattern, by means of the Evaporimeter. Sweating was stimulated in two different ways: by body heating and by parenterally administered pilocarpine. The resulting increase in evaporation was frequently measured at different positions on both sides of the forehead, and the possibility of variations in the pattern related to the passage of time was specifically scrutinized. Some typical patterns emerged. The previously reported, marked asymmetries of response (deficient heat-induced sweating and pilocarpine supersensitivity of the symptomatic side) at the medial positions in the forehead were confirmed. However, the asymmetries invariably faded to some extent with the passage of time. Patients with cluster headache show gross similarities with, but also some minor differences from, the sweat pattern of patients with brain stem lesions causing a Horner's syndrome. A subdivision of the material into groups in accordance with the pupillometric pattern after sympathomimetic stimulation made it clear that the cases of definite evaporimetric asymmetries ("typical reactions") belonged to the group with a typical pupillometric pattern. These results suggest that from an "autonomic" point of view, subpopulations may exist within the clinical entity of cluster headache.

Cervicogenic headache: the forehead sweating pattern

Forehead sweating in 11 patients with cervicogenic headache was tested with the Evaporimeter. All were studied during heating experiments, 2 patients during exercise, and 10 patients after pilocarpine stimulation. Five patients were studied during spontaneous attacks. The evaporation during spontaneous attacks was symmetrical. This was also the case after heating, exercise, and pilocarpine stimulation. These findings differ clearly from the situation in cluster headache. These observations indicate that cervicogenic headache and cluster headache differ fundamentally with regard to autonomic involvement.

Effect of isotretinoin on eccrine gland function

Sweat secretion rate, stimulated by iontophoresis of pilocarpine, was measured before and during treatment with isotretinoin in 20 patients. Sweat secretion was increased during treatment in 15 patients (75%), but the mean increase of 15% was not statistically significant (P = 0.085, paired t-test; 95% confidence limits-0.2% to +30%) and no patients had a clinically apparent alteration of sweating. We conclude that there is no important change in stimulated sweating associated with isotretinoin therapy.