Dermatológica ISO: 75-85 (1975)
Nature of the Sweat Glands in the Hairy Skin of the Beagle D.W.K. C otton , P.
van
H asselt and A.M.G. Bergers
Department of Dermatology (Prof. Dr. J.W.H. M ali) and Department of General Neurophysiology (Prof. Dr. G.P.M. H orsten), University of Nijmegen, Nijmegen
Key Words. Sweat glands • Electron microscopy • Beagle Abstract. The local pharmacology, the thermal response and the response to hypo thalamic stimulation of the sweat glands of the hairy surface of the beagle are described. The results, together with those of electron-microscopic examinations, support the idea that these sweat glands are apocrine and are not directly innervated. No clear relation ship with thermoregulation could be found and a pheromonal function is tentatively sug gested.
Received: November 28, 1974; accepted: December 12, 1974.
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 3/8/2018 5:49:59 AM
In a previous report [1], we have described experimental studies on the nature of the sweat glands on the hairy surface of the beagle. The work reported here is concerned with further investigations into this problem in cluding the role of the hypothalamus, and the effects of environmental tem perature, of local pharmacologic agents and of some behavioural stimuli on these glands. A recent report by B ell and M ontagna [2] described the histological demonstration of sweat glands in the hairy skin of horses and dogs. They demonstrated cholinesterase activity in the region of the sweat glands in the horse but were unable to do so in the dog. This is curious since the horse has always been thought to sweat as a response to circulating catecholamines, whereas indirect data suggest a nervous control of sweating in the dog [3], We have, therefore, performed a number of pharmacological and thermal tests to see if we could clarify the nature of these glands and their physiologi-
76
C otton/ van H asselt/B ergers
cal activators. Since no electron-microscopic (EM) studies have been reported in the literature, we have examined these glands from this point of view too. Finally, we have made a preliminary investigation into some behavioural stimuli in order to see if the function of these glands might include a phero monal component. Pheromones may be defined as substances produced by one individual that modify the behaviour of another individual; they are often described as ‘social hormones’. Such pheromones may be intra- or inter-speciesspecific. The literature on mammalian skin glands as organs of communica tion has recently been reviewed [11]. The possibility that sweating in the dog has a pheromonal component is indicated by the fact that the only physiologi cal stimulus that produced sweating in our experiments was copulation.
Sweat Responses to Various Drugs Various drugs at various concentrations were injected intradermally in a volume of 0.1 ml physiological saline into the shaved hairy flank skin of six adult healthy beagles (males). The sweat responses were followed continuously by use of the ‘Meeco’ electrolytic water vapour analyzer used in the fashion described by Spruit and M alten [4]. The prin ciple is that dry (< 5 ppm water) nitrogen gas is conducted via Teflon tubing to a 0.2 cm2 cup, applied lightly to the shaved skin surface. The water appearing on the skin surface under the cup evaporates into the dry nitrogen and is carried to the Meeco. In the Meeco the water electrolyses an H2SO, or P20 5 cell (depending on the model) and the resulting potential difference is recorded on a flat-bed (Servoger) recorder as a continuous trace. The injection needles are introduced into the skin such that the point of the needle comes to lie under the middle of the cup. A base line is recorded until a horizontal line occurs representing simple diffusion of water, ‘insensible perspiration’. The dogs were anaesthe tized with intravenous thiopental (25 mg/kilo) and maintained with a haIothane/N20 / 0 2 mixture. The drugs employed were the standard pharmaceutical preparations diluted immedi ately before use with sterile physiological saline at room temperature. Drugs were tested over a wide range of concentrations ( 10“19—10 4 g/0.1 ml saline) and dose response curves were plotted. The effect of atropine on the response was also studied. Drugs employed included: histamine, 5HT (serotonin), adrenaline, noradrenaline, acetylcholine, isoprenaline, and atropine. Various sex hormones (testosterone, oestradiol, progesterone) were also applied locally, intravenously, and intramuscularly. In the last case the sweat records were continued for 2 h. Following active sweating as a reponse to acetylcholine, biopsies w'crc taken from the injected areas. Control biopsies were taken from comparable uninjectcd sites and from comparable sites injected with physiological saline. Details of the prep aration of the EM photos are exactly the same as w
Nature of the Sweat Glands in the Hairy Skin of the Beagle D.W.K. C otton , P.
van
H asselt and A.M.G. Bergers
Department of Dermatology (Prof. Dr. J.W.H. M ali) and Department of General Neurophysiology (Prof. Dr. G.P.M. H orsten), University of Nijmegen, Nijmegen
Key Words. Sweat glands • Electron microscopy • Beagle Abstract. The local pharmacology, the thermal response and the response to hypo thalamic stimulation of the sweat glands of the hairy surface of the beagle are described. The results, together with those of electron-microscopic examinations, support the idea that these sweat glands are apocrine and are not directly innervated. No clear relation ship with thermoregulation could be found and a pheromonal function is tentatively sug gested.
Received: November 28, 1974; accepted: December 12, 1974.
Downloaded by: Univ. of California Santa Barbara 128.111.121.42 - 3/8/2018 5:49:59 AM
In a previous report [1], we have described experimental studies on the nature of the sweat glands on the hairy surface of the beagle. The work reported here is concerned with further investigations into this problem in cluding the role of the hypothalamus, and the effects of environmental tem perature, of local pharmacologic agents and of some behavioural stimuli on these glands. A recent report by B ell and M ontagna [2] described the histological demonstration of sweat glands in the hairy skin of horses and dogs. They demonstrated cholinesterase activity in the region of the sweat glands in the horse but were unable to do so in the dog. This is curious since the horse has always been thought to sweat as a response to circulating catecholamines, whereas indirect data suggest a nervous control of sweating in the dog [3], We have, therefore, performed a number of pharmacological and thermal tests to see if we could clarify the nature of these glands and their physiologi-
76
C otton/ van H asselt/B ergers
cal activators. Since no electron-microscopic (EM) studies have been reported in the literature, we have examined these glands from this point of view too. Finally, we have made a preliminary investigation into some behavioural stimuli in order to see if the function of these glands might include a phero monal component. Pheromones may be defined as substances produced by one individual that modify the behaviour of another individual; they are often described as ‘social hormones’. Such pheromones may be intra- or inter-speciesspecific. The literature on mammalian skin glands as organs of communica tion has recently been reviewed [11]. The possibility that sweating in the dog has a pheromonal component is indicated by the fact that the only physiologi cal stimulus that produced sweating in our experiments was copulation.
Sweat Responses to Various Drugs Various drugs at various concentrations were injected intradermally in a volume of 0.1 ml physiological saline into the shaved hairy flank skin of six adult healthy beagles (males). The sweat responses were followed continuously by use of the ‘Meeco’ electrolytic water vapour analyzer used in the fashion described by Spruit and M alten [4]. The prin ciple is that dry (< 5 ppm water) nitrogen gas is conducted via Teflon tubing to a 0.2 cm2 cup, applied lightly to the shaved skin surface. The water appearing on the skin surface under the cup evaporates into the dry nitrogen and is carried to the Meeco. In the Meeco the water electrolyses an H2SO, or P20 5 cell (depending on the model) and the resulting potential difference is recorded on a flat-bed (Servoger) recorder as a continuous trace. The injection needles are introduced into the skin such that the point of the needle comes to lie under the middle of the cup. A base line is recorded until a horizontal line occurs representing simple diffusion of water, ‘insensible perspiration’. The dogs were anaesthe tized with intravenous thiopental (25 mg/kilo) and maintained with a haIothane/N20 / 0 2 mixture. The drugs employed were the standard pharmaceutical preparations diluted immedi ately before use with sterile physiological saline at room temperature. Drugs were tested over a wide range of concentrations ( 10“19—10 4 g/0.1 ml saline) and dose response curves were plotted. The effect of atropine on the response was also studied. Drugs employed included: histamine, 5HT (serotonin), adrenaline, noradrenaline, acetylcholine, isoprenaline, and atropine. Various sex hormones (testosterone, oestradiol, progesterone) were also applied locally, intravenously, and intramuscularly. In the last case the sweat records were continued for 2 h. Following active sweating as a reponse to acetylcholine, biopsies w'crc taken from the injected areas. Control biopsies were taken from comparable uninjectcd sites and from comparable sites injected with physiological saline. Details of the prep aration of the EM photos are exactly the same as w
