The distribution of substance P-like (SP) and vasoactive intestinal polypeptide-like (VIP) structures was studied using an indirect immunoperoxidase technique in the mediterranean barbel Barbus meridionalis and in the rainbow trout Salmo gairdneri. SP-like positive fibers were observed in the inner strata of the mediterranean barbel olfactory bulb, mainly the granule cell and the plexiform layers. Ganglion cells and fibers of the terminal nerve were also labeled. No SP-positive structure was found in the olfactory bulb of the rainbow trout. On the contrary, the VIP antiserum used displayed very strong immunostaining in the olfactory nerve fiber layer of Salmo gairdneri, whereas those fibers in Barbus meridionalis showed no immunoreactivity. After a complete transection of the olfactory tract and a survival time of 20 days, SP-immunostained fibers were not observed. Thus, they can presumably be identified as centrifugal fibers, coursing from the telencephalic hemispheres through the olfactory tracts, into the olfactory bulb. The VIP immunoreactivity was confined to the olfactory fibers, both in the olfactory nerve and the olfactory bulb. The positive immunostaining disappeared after chemical lesion of the olfactory mucosa. These observations demonstrate that the olfactory bulb of freshwater teleosts exhibits a high degree of heterogeneity in its immunocytochemical distribution pattern, this pattern also differing from previous reports on higher vertebrates.
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http://dx.doi.org/10.1002/jnr.490250113 | DOI Listing |
Sci Rep
January 2025
The Department of Cellular and Integrative Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Fragile X syndrome (FXS) is a neurodevelopmental disorder oftentimes associated with abnormal social behaviors and altered sensory responsiveness. It is hypothesized that the inappropriate filtering of sensory stimuli, including olfaction, can lead to aberrant social behavior in FXS. However, previous studies investigating olfaction in animal models of FXS have shown inconsistent results.
View Article and Find Full Text PDFZool Res
January 2025
School of Basic Medicine, Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Brain Diseases, Qingdao University, Qingdao, Shandong, 266071, China. E-mail:
Iron is the most abundant transition metal in the brain and is essential for brain development and neuronal function; however, its abnormal accumulation is also implicated in various neurological disorders. The olfactory bulb (OB), an early target in neurodegenerative diseases, acts as a gateway for environmental toxins and contains diverse neuronal populations with distinct roles. This study explored the cell-specific vulnerability to iron in the OB using a mouse model of intranasal administration of ferric ammonium citrate (FAC).
View Article and Find Full Text PDFNat Commun
January 2025
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
While animals readily adjust their behavior to adapt to relevant changes in the environment, the neural pathways enabling these changes remain largely unknown. Here, using multiphoton imaging, we investigate whether feedback from the piriform cortex to the olfactory bulb supports such behavioral flexibility. To this end, we engage head-fixed male mice in a multimodal rule-reversal task guided by olfactory and auditory cues.
View Article and Find Full Text PDFJ Physiol Sci
January 2025
Department of Autonomic Neuroscience, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2 Sakaecho, Itabashi-ku, 173-0015, Tokyo, Japan.
The olfactory bulb receives cholinergic basal forebrain inputs as does the neocortex. With a focus on nicotinic acetylcholine receptors (nAChRs), this review article provides an overview and discussion of the following findings: (1) the nAChRs-mediated regulation of regional blood flow in the neocortex and olfactory bulb, (2) the nAChR subtypes that mediate their responses, and (3) their activity in old rats. The activation of the α4β2-like subtype of nAChRs produces vasodilation in the neocortex, and potentiates olfactory bulb vasodilation induced by olfactory stimulation.
View Article and Find Full Text PDFFront Neurosci
January 2025
Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
In the ventricular-subventricular-zone (V-SVZ) of the postnatal mammalian brain, immature neurons (neuroblasts) are generated from neural stem cells throughout their lifetime. These V-SVZ-derived neuroblasts normally migrate to the olfactory bulb through the rostral migratory stream, differentiate into interneurons, and are integrated into the preexisting olfactory circuit. When the brain is injured, some neuroblasts initiate migration toward the lesion and attempt to repair the damaged neuronal circuitry, but their low regeneration efficiency prevents functional recovery.
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