Galanin expression in adult human dorsal root ganglion neurons: initial observations

• Published in: Neuroscience Vol. 117; no. 4; pp. 795 - 809
• Main Authors: Landry, M, Åman, K, Dostrovsky, J, Lozano, A.M, Carlstedt, T, Spenger, C, Josephson, A, Wiesenfeld-Hallin, Z, Hökfelt, T
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.01.2003; Elsevier
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; calcitonin gene-related peptide; Calcitonin Gene-Related Peptide - genetics; Cell Size - physiology; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; coexistence; Female; Fundamental and applied biological sciences. Psychology; Galanin - genetics; Ganglia, Spinal - metabolism; Ganglia, Spinal - pathology; Ganglia, Spinal - physiopathology; Headache - metabolism; Headache - pathology; Headache - physiopathology; Herpes Zoster - metabolism; Herpes Zoster - pathology; Herpes Zoster - physiopathology; Humans; Male; Medicin och hälsovetenskap; Middle Aged; nerve injury; Neurons, Afferent - metabolism; Neurons, Afferent - pathology; neuropeptides; Nociceptors - metabolism; Nociceptors - pathology; Nociceptors - physiopathology; pain; Pain - metabolism; Pain - pathology; Pain - physiopathology; Peripheral Nerve Injuries; Peripheral Nerves - metabolism; Peripheral Nerves - physiopathology; Peripheral Nervous System Diseases - metabolism; Peripheral Nervous System Diseases - pathology; Peripheral Nervous System Diseases - physiopathology; Postmortem Changes; RNA, Messenger - metabolism; substance P; Substance P - genetics; Vertebrates: nervous system and sense organs; pain; NP; SSC; coexistence; TdT; calcitonin gene-related peptide; neuropeptides; mRNA; L; PHI; Th; nerve injury; DRG; PBL; substance P; CGRP; Human; Spinal cord; Galanin; Central nervous system; Calcitonin gene related peptide; Coexistence; Gene expression; Neuropeptide; Ganglion neuron; Spinal ganglion
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/S0306-4522(02)00965-X

Human dorsal root ganglia (DRGs) were obtained during various procedures and processed for single and double in situ hybridisation using oligonucleotide probes complementary to three peptide mRNAs. Some postmortem ganglia were also analysed. In donor (unlesioned) DRGs 12.5% of the neuron profiles (NPs) were galanin mRNA-positive (mRNA +), 47.5% calcitonin gene-related peptide (CGRP) mRNA + and 32.7% substance P mRNA +. The corresponding percentages for cervical/thoracic DRGs from patients suffering from severe brachial plexus injury were 32.8%, 57.4% and 34.5%, respectively. In these DRGs a high proportion of the galanin mRNA + NPs contained CGRP mRNA and substance P mRNA. In DRGs from a patient with migraine-like pain a comparatively small proportion expressed galanin, whereas in DRGs from a herpes zoster patient galanin mRNA + NPs were comparatively more frequent. The results from human postmortem DRGs revealed only weak peptide mRNA signals. The present results demonstrate that galanin is expressed in DRGs not only in a number of animal species including monkey as previously shown, but also in a considerable proportion of human DRG neurons, often together with CGRP and substance P, and mostly in small neurons. Thus, galanin may play a role in processing of sensory information, especially pain, in human DRGs and dorsal horn. However, to what extent a similarly dramatic upregulation of galanin expression can be seen after peripheral nerve lesion in man, as has been reported for rat, mouse and monkey, remains to be analysed.