title: Age-related changes of neurochemically different subpopulations of cardiac spinal afferent neurons in rats.
abstract: This study investigated the effect of aging on cardiac spinal afferent neurons in the rat. A patch loaded with retrograde tracer Fast Blue (FB) was applied to all chambers of the rat heart. Morphological and neurochemical characteristics of labeled cardiac spinal afferent neurons were assessed in young (2 months) and old (2 years) rats using markers for likely unmyelinated (isolectin B4; IB4) and myelinated (neurofilament 200; N52) neurons. The number of cardiac spinal afferent neurons decreased in senescence to 15% of that found in young rats (1604 vs. 248). The size of neuronal soma as well as proportion of IB4+ neurons increased significantly, whereas the proportion of N52+ neurons decreased significantly in senescence. Unlike somatic spinal afferents, neurochemically different populations of cardiac spinal afferent neurons experience morphological and neurochemical changes related to aging. A major decrease in total number of cardiac spinal afferent neurons occurs in senescence. The proportion of N52+ neurons decreased in senescence, but it seems that nociceptive innervation is preserved due to increased proportion and size of IB4+ unmyelinated neurons.
authors.affiliation: Department of Anatomy, Histology and Embriology, School of Medicine in Split, Šoltanska 2, 21000 Split, Croatia. maja.marinovic.guic@mefst.hr
authors.forename: Maja Marinović
authors.initials: MM
authors.lastname: Guić
authors.forename: Branka
authors.initials: B
authors.lastname: Runtić
authors.forename: Vana
authors.initials: V
authors.lastname: Košta
authors.forename: Jure
authors.initials: J
authors.lastname: Aljinović
authors.forename: Ivica
authors.initials: I
authors.lastname: Grković
mesh_terms: D000818:Animals; D016922:Cellular Senescence / Q000502:physiology*; D005260:Female; D006023:Glycoproteins / Q000378:metabolism; D006321:Heart / Q000294:innervation*; D037102:Lectins / Q000378:metabolism; D023421:Models, Animal; D016900:Neurofilament Proteins / Q000378:metabolism; D009475:Neurons, Afferent / Q000145:classification* / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013127:Spinal Nerves / Q000166:cytology*; D053675:Versicans
chemical_list: D006023:Glycoproteins; D037102:Lectins; D016900:Neurofilament Proteins; C508324:Vcan protein, rat; C051774:neurofilament protein H; D053675:Versicans
keywords: Afferent neurons; DRG; Heart innervation; IB(4); N52; Senescence