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Query: UMLS:C0162473 (Frey)
 2,599 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The response of C polymodal nociceptors to thermal and mechanical stimuli applied to the monkey's face was recorded extracellulary in the trigeminal ganglion in rhesus monkeys anesthetized with sodium pentobarbital. Conduction velocities, determined from electrical stimulation of receptive fields (RFs), were in the range for unmyelinated C fibers (mean=0.82 m/s, n=20; SD=+/-0.17). With two exceptions cutaneous RFs were single spots (median=2 mm2; n=37) and usually were identical for thermal and mechanical stimuli. The median force threshold for the sample of units was 1.2 g (von Frey technique; n = 39; range = 0.07-8.5 g). 2. Discharges to thermal stimuli were investigated with a feedback-controlled contact thermode which permitted temperature changes less than or equal 12.0 degrees C/s. Thermal thresholds ranged from 38 degree to 49 degree C (median=46 degrees C; n=37), and maximum discharge frequencies were obtained in the noxious heat range (45-55 degrees C). For a graded series of 5 s duration stimuli from an adapting temperature of 35 degrees C, the number of impulses increased as a monotonic function of stimulus intensity over the range from threshold temperature to 50-53 degrees C. Many stimulus-response functions were positively accelerated, and linear regression analyses showed that most units examined were best fit by nonlinear functions. 3. The typical pattern of activity to 5 s duration temperature shifts into the noxious heat range was a short accelerating burst of impulses followed by deceleration to a lower rate of discharge prior to termination of the stimulus. The temporal profile of the discharge of impulses was virtually identical at different adapting temperatures. In units tested with 30 s duration stimuli at 2-6 degrees C above threshold, the mean frequency of discharge during the final 25 s was 1.46 impulses/s (n=6; SD=+/-0.89). 4. Application of noxious heat stimuli a few degrees above threshold temperature typically sensitized or enhanced the response of the unit to subsequent application of heat stimuli. The signs of sensitization consisted of a decrease in threshold temperature, increased frequency of discharge, decreased latency to the first impulse, and afterdischarges. Units failed to respond throughout the duration of 30 s stimuli if the final temperature exceeded 50 degrees C. Depressed responses were sometimes produced by application of intense (greater than or equal 55 degrees C) stimuli, presumably as a result of partial inactivation of the receptor. 5. In a correlative analysis, the latency and pattern of discharge in a sample of units were compared with escape responses in two monkeys to temperature shifts into the noxious heat range (49 and 51 degrees C). The analysis revealed that the discharge of C polymodal nociceptors alone cannot account for fast escape responses, but the discharge may contribute to escape responses which occur more than 3.5 s after the onset of stimulation.
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PMID:Response of unmyelinated (C) polymodal nociceptors to thermal stimuli applied to monkey's face. 82 19

We attempted to develop an experimental animal model for peripheral neuropathic pain. Under sodium pentobarbital anesthesia, both the L5 and L6 spinal nerves (group 1) or the L5 spinal nerve alone (group 2) of one side of the rat were tightly ligated. For comparison, a parallel study was conducted with another group of rats (group 3) which received a partial tight sciatic nerve ligation, a paradigm developed previously as a neuropathy model. Withdrawal latencies to application of radiant heat to the foot were tested for the next 16 weeks in all 3 groups. Sensitivity of the hind paw to mechanical stimulation was tested with von Frey filaments. The general behavior of each rat was noted during the entire test period. Results suggested that the surgical procedure in all 3 groups produced a long-lasting hyperalgesia to noxious heat (at least 5 weeks) and mechanical allodynia (at least 10 weeks) of the affected foot. In addition, there were behavioral signs of the presence of spontaneous pain in the affected foot. Therefore, we believe we have developed an experimental animal model for peripheral neuropathy using tight ligations of spinal nerves. The model manifests the symptoms of human patients with causalgia and is compatible with a previously developed neuropathy model. The present model has two unique features. First, the surgical procedure is stereotyped. Second, the levels of injured and intact spinal segments are completely separated, allowing independent experimental manipulations of the injured and intact spinal segments in future experiments to answer questions regarding mechanisms underlying causalgia.
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PMID:An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat. 133 81

Frey's medium supplemented with artificial liposomes substituting for serum was evaluated for Mycoplasma gallisepticum (MG) serum plate agglutination (SPA) antigen. Antigens prepared in batch (static) culture were compared with antigens grown in a fermenter. All batch-grown MG liposome antigens were highly sensitive, specific, and resulted in a greater yield compared with fermenter-grown liposome antigens. Compared with antigens prepared in Frey's medium with 12% swine serum (regular FMS) or with commercial SPA antigens, liposome antigens had a higher degree of specificity; however, they were similar in sensitivity and antigen yield. The only growth parameter to affect the yield per liter of batch-grown liposome antigen was the concentration of liposomes in the growth medium. The reduced yield and sensitivity of antigens grown in a fermenter may have been due to autoclaving the medium instead of sterilizing by filtration. There was no obvious difference between patterns of serum-medium-grown, liposome-medium-grown, or commercial SPA antigens upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
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PMID:Further studies of Mycoplasma gallisepticum serum plate agglutination antigen grown in medium with artificial liposomes substituting for serum. 246 43

The effects of halothane on the responses of C-fiber (CMHs) and A-fiber (AMHs) nociceptive afferents sensitive to mechanical and heat stimuli were studied in monkeys. The response to heat stimuli was studied with use of a laser thermal stimulator that provided stepped increases in skin temperature over a 7.5-mm-diameter area with rise times to the desired temperature near 100 ms. Recordings were obtained from single fibers that innervated the glabrous skin of the hand using a teased-fiber dissection technique. In initial studies the response of 32 CMHs and 45 AMHs in monkeys anesthetized with pentobarbital sodium (3-6 mg X kg-1 X h-1) was compared with the response of 12 CMHs and 23 AMHs in monkeys anesthetized with a combination of halothane (0.8%) and N2O (67%). A standardized set of 10 3-s heat stimuli ranging from 41 to 49 degrees C delivered every 30 s were applied to the receptive field. Both AMHs and CMHs had a lower threshold and greater response to suprathreshold heat stimuli under conditions of halothane-N2O anesthesia. The threshold to mechanical stimuli, as tested by von Frey hairs, was not significantly different. Five CMHs and 5 AMHs were studied in a crossover study in which responses to the 41-49 degrees C stimuli were obtained first under halothane-N2O (0.8%-67%) anesthesia, then under an ultrashort acting barbiturate, methohexital (2-9 mg/kg over 15 min), and finally once again under halothane-N2O anesthesia. For the five CMHs, the mean cumulative response was 1.8 times greater, whereas for the five AMHs the response was 4.7 times greater under halothane as opposed to barbiturate anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Halothane sensitizes cutaneous nociceptors in monkeys. 649 15

Fully developed eccrine glands distributed over the entire integument are found only in man. The secretory mechanism is based on the active transport of sodium ions; water diffuses passively following the osmotic gradient. The thermoregulatory center in the hypothalamic region receives impulses from external and internal thermoreceptors and is modified by levels of hormones, by emotions, physical activity and pyrogens. Heat loss is controlled by the blood flow through the skin and by activity of eccrine glands. Thermoregulatory sweating occurs mainly on head and trunk. Emotions trigger eccrine sweating predominantly in the axillae, on palms, and soles. Generalized hyperhidrosis is mostly due to metabolic or endocrinologic disorders; in the state of acclimatization or following menopause hyperhidrosis is conceived to be physiologic. In underlying neurologic disorders hyperhidrosis follows a segmental or irregular pattern. Functional or anatomic eccrine nevi have been described. Gustatory sweating elicited by certain foods is found to be idiopathic and occurs symmetrically on the face. Subsequent to neurologic lesions (e.g., Frey's syndrome) gustatory sweating in segmental distribution may be associated with salivation and can be triggered by any foodstuff. The idiopathic localized hyperhidrosis of axillae, palms, and soles poses a frequent therapeutic problem in the dermatologist's office. Frequently, a familial predisposition is found. To what extent the disorder may be part of a general imbalance of psychovegetative functions is not yet fully understood.
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PMID:[Physiopathologic aspects and clinical pictures in hyperhidrosis]. 666 23

We attempted to develop an experimental animal model using rat's tail for understanding the mechanisms involving peripheral neuropathic pain. Under sodium pentobarbital anesthesia, the left inferior caudal trunk of the rat was resected between the S3 and S4 spinal nerves. Latencies of tail-flick induced by the stimulus such as warm (40 degrees C) and cold (4 degrees C) water to the tail were measured for the following 30 weeks. In addition, sensitivity of the tail to mechanical stimulation was tested with von Frey hairs on these rats. Operated rats showed abnormal sensitivity of the tail to normally innocuous mechanical and thermal (warm and cold) stimuli. We interpreted these results as signs of neuropathic pain following nerve injury. The present model offers several advantages in performing behavioral tests; (1) it is easy to apply thermal stimulation to the rat's tail using a water bottle; (2) it is easy to apply the mechanical stimulation with von Frey hairs and to localize sensitive areas in the tail; and (3) blind behavioral studies are possible due to the lack of deformity in the tail after surgery.
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PMID:A behavioral model for peripheral neuropathy produced in rat's tail by inferior caudal trunk injury. 782 81

Two-dimensional crystals of beef heart mitochondrial cytochrome c oxidase dimers were labeled at Cys-115 of subunit III with a monomaleimide derivative of an undecagold cluster compound. The binding site of the gold cluster compound and hence the site of subunit III were identified by image processing of cryoelectron micrographs of the crystals preserved in a mixture of glucose and uranyl acetate. The shape of the cytochrome oxidase dimer can be approximated as a parallelogram which is 44 by 82 A with an included angle of 80 degrees oriented with its long dimension along the a axis of the crystal. Labeling of subunit III was confirmed by a shift in the mobility of approximately 50% of subunit III molecules upon electrophoresis in polyacrylamide gels in the presence of sodium dodecyl sulfate. Averaged images of undecagold cluster labeled crystals and of unlabeled crystals were calculated; each image represents an average of approximately 17,000 molecules of either labeled or unlabeled cytochrome oxidase. On the basis of a statistical analysis of the differences between the two images, the gold cluster binds along a line 30 degrees from the a axis and 29 A from the center of the dimer. This result is interpreted in the context of other structural studies including the site of cytochrome c binding which Frey and Murray found to be near the a axis and 18 A from the center of the dimer [Frey, T. G., & Murray, J. M. (1994) J. Mol. Biol. 237, 275-297].(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Electron microscopy of cytochrome c oxidase crystals: labeling of subunit III with a monomaleimide undecagold cluster compound. 794 82

Mycoplasma gallisepticum- or M. synoviae-challenged chickens were monitored with serological assays (serum plate agglutination, hemagglutination inhibition, and enzyme-linked immunosorbent assay) and polymerase chain reaction (PCR). The tracheal swabs from M. gallisepticum-challenged chickens received three different treatments (phosphate-buffered saline [PBS], Frey's broth, or 10 mM Tris-HCl/250 mM ethylenediaminetetraacetic acid/ 2.5% sodium dodecyl sulfate [STE]) prior to DNA purification. A nonphenolic method for DNA extraction was utilized. The best PCR results were obtained with PBS swab treatment. The nonphenolic method for DNA extraction was compared with a phenolic method in an experiment with tracheal swabs from M. synoviae-challenged chickens and commercial flocks. Both methods gave comparable results.
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PMID:Polymerase chain reaction optimization for Mycoplasma gallisepticum and M. synoviae diagnosis. 871 37

Behavioral and electrophysiological methods were used to investigate the hyperalgesia and allodynia, and functional changes in lumbar spinal dorsal horn neurons, in a model of neuropathic pain (Selzer et al. 1990) involving ligation of one-third to one-half of one sciatic nerve in rats. One and 5 weeks following ligation, there was a significant reduction in hind limb withdrawal latency to noxious radiant heat on the operated side and, to a lesser degree, on the unoperated side. By 16 weeks, heat withdrawal latencies were reduced about equally (approximately 40%) on both sides. Withdrawal threshold to mechanical pressure was markedly reduced within 1 week on the operated side, and decreased in a time-dependent manner on the unoperated side. Heat withdrawal latency and von Frey withdrawal thresholds were not significantly affected in sham-operated rats. The same rats were tested in a paradigm measuring the isometric force of hind limb withdrawals elicited by graded noxious contact heat stimuli (38-52 degrees C, 5 sec). Withdrawal force increased monotonically with stimulus temperature starting at a threshold of approximately 40 degrees C. Stimulus-response functions were not significantly different between a sham-operated group and groups tested 5 (acute) and 16 weeks (chronic) after partial sciatic nerve ligation. Following behavioral testing, the animals were deeply anesthetized with pentobarbital sodium to allow electrophysiological recording of responses of single lumbar dorsal horn wide-dynamic range-type neurons to mechanical and noxious thermal stimulation of the hind paw. Recordings were made from 6 sham-operated rats (26 neurons ipsilateral and 31 contralateral to the operated leg), from 7 rats receiving partial sciatic nerve ligation 5 weeks previously (29 ipsilateral and 29 contralateral to ligation), and from 7 rats receiving partial sciatic ligation 16 weeks previously (18 ipsilateral, 29 contralateral to ligation). In several ligated rats we were unable to find heat-responsive neurons with cutaneous receptive fields on the hind paw ipsilateral to the ligation. For the neurons that were sensitive to heat, responses increased monotonically from a threshold of 40-42 degrees C. Neuronal stimulus-response functions for heat were not significantly different between ipsi- and contralateral (to operated) sides in the sham, 5-week or 16-week post-ligation groups, or between sham and 5- or 16-week post-ligation groups. Mechanical receptive field areas were not significantly different between ipsi- and contralateral sides in the sham and 5-week post-ligation groups, or between sham and 5-week post-ligation groups. However, receptive field areas were significantly larger in the 16-week post-ligation group (both ipsi- and contralateral to ligation) compared to sham and 5-week post-ligation groups. The results suggest that allodynia may be associated with a chronic enhancement of neuronal mechanosensitivity, but that the thermal hyperalgesia is not associated with enhanced neuronal responsiveness or force of withdrawal.
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PMID:Behavioral and electrophysiological assessment of hyperalgesia and changes in dorsal horn responses following partial sciatic nerve ligation in rats. 888 Aug 53

In this study we investigated the receptive field properties, responses to mechanical and thermal stimuli, and sensitivity to systemic administration of pentobarbital sodium and morphine of single neurons recorded in the sacral spinal cords of pentobarbital-anesthetized rats. Fifty-three neurons responded to innocuous mechanical stimulation of the tail. Of 45 neurons that were additionally tested with noxious thermal stimulation, 62% responded and were classified as wide-dynamic-range or multireceptive neurons. Recording sites were located mainly in the middle layers of the S2-S4 dorsal horn. Mechanosensitive receptive fields on the tail varied widely in size (range 0.14-35 cm2, mean 10.33 cm2) and form, and were in nearly all cases bilateral. Most neurons responded with a high-frequency discharge followed by a more slowly adapting response to pressure stimuli delivered with von Frey hairs. Responses (maximal frequency and total number of impulses) increased in a graded manner to pressure stimuli ranging from 1.2 to 447 g. For neurons responsive to noxious heating of the tail, responses increased in a linear manner over the range of 38-54 degrees C and often leveled off at higher temperatures. Of nine neurons tested with both graded von Frey and noxious heat stimuli, mean responses (maximal frequency and total number of impulses) evoked by the strongest pressure stimuli were larger than those evoked by the most intense heat stimuli, but the difference was not statistically significant. Responses to repeated 48 degrees C stimuli were significantly attenuated within 8 min after systemic administration of morphine (1 or 2 mg/kg ip), reaching maximal suppression (to 37.3%; N = 13) after 18 min, with recovery following systemic naloxone. After morphine (1 and 2 mg/kg ip), the slope of the population stimulus-response function for noxious heat was reduced (51.8%), and the threshold was increased (by 4 degrees C). Responses to noxious heat were significantly depressed (to a mean of 54%; N = 10) by supplemental administration of pentobarbital (mean 17 mg/kg over 5 min). On the basis of similarities between the present data and previous behavioral measures of tail flick stimulus-response functions and their modulation, it is suggested that some of the present neurons might function as interneurons in the tail flick reflex arc.
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PMID:Responses of rat sacral spinal neurons to mechanical and noxious thermal stimulation of the tail. 906 34


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