Biomedical subjects
Publications and source records attributed to M J Hoffert.
Patients with migraine with aura treated each of six acute attacks with either nifedipine or vehicle administered in double-blind, randomized form. Two modes of administration were studied. Both increased the intensity of headaches compared to vehicle. We conclude that nifedipine is not useful as an abortive treatment of migraine with aura.
Elucidating the details of the changes of neural function associated with chronic pain would do more than expand our knowledge of the neurophysiology of pain. It would also help us understand the relationship of nociception to pain both in normal and pathologic conditions. Perhaps most important, it would help us more intelligently to develop treatments to reverse these pathologic changes and thus treat chronic pain more effectively.
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Thyrotropin-releasing hormone-like immunoreactivity was demonstrated in neurons within the superficial laminae (I, II, III) of the mouse spinal dorsal horn by light-microscopic peroxidase immunocytochemistry. The immunoreactivity was distributed in a narrow dorsoventral band that enclosed the substantia gelatinosa (lamina II), with a higher concentration along the lamina II/III border. At present, the functional significance of these neurons is unknown. Their existence within the substantia gelatinosa suggests a role in sensory information processing.
Dorsal column postsynaptic (DCPS) neurons in the dorsal horn of the spinal cord have been identified by antidromic stimulation and intracellularly recorded in anesthetized cats. In about one-half of the cells, the antidromic stimulus evokes only an antidromic potential. This potential sometimes has an atypical shape due to penetration-induced depolarization. Atypical potentials are converted into typical antidromic spike potentials after intracellular injection of hyperpolarizing current. In the other one-half, the antidromic potentials are followed by postsynaptic activity. Intracellular analysis indicates that this postsynaptic activity is generated largely by activation of the intraspinal collaterals of A-beta primary afferents that are ascending the dorsal columns. Part of this postsynaptic activity has been produced monosynaptically. Polysnaptic responses are also evident; these are thought to be initiated by A-beta axons, desending axons from neurons in the dorsal column nuclei, or the local collaterals of the DCPS axons themselves. The results indicate that the DCPS system is nonlemniscal in nature and may be involved in those pain modulation systems that are activated by A-beta afferents.