Brain research bulletin
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Brain research bulletin · Dec 1989
Parvalbumin- and calbindin D28k-immunoreactive neurons in the superficial layers of the spinal cord dorsal horn of rat.
Immunohistochemical techniques were utilized to investigate the distribution and morphology of neurons containing the calcium binding proteins parvalbumin (PV) and calbindin D28k (CaBP) in the superficial layers of rat spinal cord. Most PV-immunoreactive (PV-IR) neurons were restricted to a 25 to 60 microns thick band straddling the border between lamina II and III. Positive somata had long rostrocaudally oriented dendrites confined to narrow sagittally arranged sheets within this band and axons that entered lamina II or the superficial portions of lamina III. ⋯ However, dorsal rhizotomy reduced the number of positive axons in the dorsal column and in deeper lamina of the dorsal horn. These results add to the known lamination patterns of the superficial dorsal horn and point to the existence of a lamina defined by PV-positive neurons at the lamina II/III border. These neurons may have electrophysiological characteristics attributed to PV- or CaBP-containing neurons elsewhere in the CNS.
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Brain research bulletin · Apr 1989
Afferent and efferent connections of the cholinoceptive medial pontine reticular formation (region of the ventral tegmental nucleus) in the cat.
Following minor concussive brain injury when there is an otherwise general suppression of CNS activity, the ventral tegmental nucleus of Gudden (VTN) demonstrates increased functional activity (32). Electrical or pharmacological activation of a cholinoceptive region in this same general area of the medial pontine tegmentum contributes to certain components of reversible traumatic unconsciousness, including postural atonia (31, 32, 45). Therefore, in an effort to examine the neuroanatomical basis of the behavioral suppression associated with a reversible traumatic unconsciousness, the afferent and efferent connections of the VTN and putative cholinoceptive medial pontine reticular formation (cmPRF) were studied in the cat using the retrograde horseradish peroxidase (HRP), HRP/choline acetyltransferase (ChAT) double-labeling immunohistochemistry, and anterograde HRP and autoradiographic techniques. ⋯ The majority of fibers ascended to terminate in the medial and lateral mammillary nuclei, interpeduncular complex (especially paramedian subnucleus), ventral tegmental area, lateral hypothalamus, and the medial septum in the basal forebrain. Labeling that joined the mammillothalamic tract to terminate in the anterior nuclear complex of the thalamus was thought to occur transneuronally. Some projections were also observed to nucleus reticularis pontis oralis and caudalis, superior central nucleus, and dorsal tegmental nucleus adjacent to the VTN...
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Brain research bulletin · Mar 1987
A note on the projections of pars compacta neurons within pars reticulata of the substantia nigra in the rat.
The ascending projections of pars compacta (SNc) neurons displaced within the pars reticulata (SNr) of the substantia nigra in the rat were examined using a fluorescent retrograde tracing. Following unilateral injections of a tracer into the striatum, SNc cells within the SNr were retrogradely labeled predominantly in the caudal parts, and to a lesser extent in the rostral portions of the nucleus. ⋯ Injections of a tracer into the nucleus accumbens (Acc) did not produce any labeling of these displaced SNc cells in contrast with cells in the SNc proper. Given that the SNc neurons within the SNr project only to the striatum but not to the Acc, and that they contain dopamine but not cholecystokinin, they might be involved in the motor but not in the limbic function.
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Brain research bulletin · Feb 1987
The effect of a fever-like response on the secondary antibody response of the rat.
Since fever appears to modulate the primary humoral immune response, a fever-like response was induced in 18 rats by cooling their preoptic areas during the first five days after re-immunization with sheep erythrocytes. The titre of antibodies in these rats was the same as that in 17 control animals, indicating that the febrile response does not influence the magnitude of the secondary antibody response. It is suggested that only those fevers evolving in the early phase of a primary, natural infection may modulate the magnitude of the humoral immune response to the pathogen.
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Brain research bulletin · Jul 1986
Monosodium glutamate neurotoxicity: a sex-specific impairment of blood pressure but not vasopressin in developing rats.
Neonatal administration of monosodium glutamate (MSG) results in severe adenohypophyseal endocrine malfunction as a result of hypothalamic neurotoxic lesioning. The present study examined the effects of administration of MSG on the neurohypophyseal vasopressinergic (AVP) system and systolic blood pressure (SBP) in adulthood. Monosodium glutamate or hypertonic sodium chloride was administered to male and female rat pups on days 1, 3, 5, 7 and 9 after birth. ⋯ Female MSG-treated rats, unlike male MSG-treated rats, exhibited consistent systolic hypotension when compared with the NaCl-treated or non-treated control rats at 6, 9 and 12 weeks of age. Despite this chronic hypotension in MSG-treated female rats, heart rate was not altered and serum AVP was not elevated. These observations suggest a resetting of the baroreflex, attributable to neonatal administration of MSG.