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Preproenkephalin upregulation in nucleus caudalis: High and low intensity afferent stimulation differentially modulate early and late responses
Author(s) -
Nishimori Toshikazu,
Buzzi M. Gabriella,
Chudler Eric H.,
Poletti Charles E.,
Moskowitz Michael A.,
Uhl George R.
Publication year - 1990
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903020422
Subject(s) - stimulation , capsaicin , nucleus , neuroscience , stimulus (psychology) , downregulation and upregulation , nociception , immediate early gene , afferent , biology , parabrachial nucleus , medicine , endocrinology , gene expression , receptor , psychology , gene , biochemistry , psychotherapist
Nucleus caudalis expression of preproenkephalin mRNA changes following lesions depleting small‐caliber primary afferent fibers and after stimulation of trigeminal afferents at different intensities. Animals treated neonatally with capsaicin display reduced preproenkephalin gene expression in nucleus caudalis neurons. Stimulation of normal animals at low intensities enhances preproenkephalin expression in a bimodal temporal pattern. High intensity stimulation is effective only at later time points in normal animals, but it causes both early and late effects on preproenkephalin expression when applied to animals neonatally lesioned with capsaicin. Transsynaptic regulation of preproenkephalin expression in pain‐modulating areas of the nucleus caudalis of the trigeminal nerve thus depends on the specific type of primary afferent input. The rapid responses noted after selective large fiber stimulation appear to be suppressed by coactivation of small caliber fibers. Later responses appear less influenced by the quality of the eliciting afferent stimulus.