The Journal of physiology
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The Journal of physiology · Jul 1987
Responses of spinothalamic tract cells in the superficial dorsal horn of the primate lumbar spinal cord.
1. The responses of thirty-five spinothalamic tract (s.t.t.) cells in or near lamina I of the dorsal horn were examined in chloralose- and barbiturate-anaesthetized monkeys (Macaca fascicularis). Many of the cells could be classified on the basis of receptive field properties as either wide dynamic range (w.d.r.) cells or as high-threshold (h.t.) cells. 2. ⋯ It is concluded that s.t.t. cells in or near lamina I can signal noxious cutaneous stimuli but have poor coding abilities for innocuous mechanical stimuli. Some of these cells respond to innocuous thermal stimuli, but their role in thermoreception is unclear. The small receptive fields suggest that these cells could contribute to stimulus localization.
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The Journal of physiology · Jul 1987
Somatic and visceral inputs to the thoracic spinal cord of the cat: marginal zone (lamina I) of the dorsal horn.
1. Single-unit electrical activity has been recorded from fifty-five neurones whose recording sites were located in or immediately adjacent to the marginal zone (lamina I) of the lower thoracic spinal cord (T8-T12) of anaesthetized or decerebrate cats. Their responses to stimulation of somatic and visceral afferent fibres and the sizes of their cutaneous receptive fields have been analysed and compared with the responses and receptive fields of neurones recorded throughout the spinal grey matter. 2. ⋯ The majority of somatic and viscero-somatic neurones in lamina I had small somatic receptive fields but, even in this group of cells, viscero-somatic neurones had larger receptive fields than somatic cells. 6. Ascending axonal projections in both dorsolateral funiculi and in the contralateral ventrolateral quadrant were tested in eighteen lamina I neurones. Only one neurone was found to project to the cervical cord.(ABSTRACT TRUNCATED AT 400 WORDS)
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The Journal of physiology · Jul 1987
Steady-state fluid filtration at different capillary pressures in perfused frog mesenteric capillaries.
1. The theory of steady-state filtration through capillary walls (Michel, 1984) has been developed and investigated in experiments on single capillaries of the frog mesentery perfused with Ringer solutions containing bovine serum albumin (BSA) and Ficoll 70. 2. In each experiment, the micro-occlusion technique of Michel, Mason, Curry, Tooke & Hunter (1974) has been used to investigate the relation between fluid movements per unit area of capillary wall (Jv/A) and capillary pressure (Pc) under two sets of conditions in the same vessel. ⋯ E. of mean +/- 0.04) and in eight different vessels mean sigma to Ficoll 70 in the presence of BSA (10 mg ml-1) was 0.98 (S. E. of mean +/- 0.05). The steady-state data were consistent with the prediction that the oncotic pressure opposing high filtration rates approximates to sigma 2 pi c in the steady state, where pi c is the perfusate oncotic pressure.(ABSTRACT TRUNCATED AT 400 WORDS)