The morphology, and laminar and topographic distribution of fibers containing calcitonin gene-related peptide (CGRP) immunoreactivity were studied by light and electron microscopic methods in the cerebral cortex of adult cats using a rabbit antiserum raised against the C-terminal region of the rat alpha-CGRP. At the light microscopic level, a sparse number of CGRP-positive fibers were observed in the frontal, parietal, and occipital cortices. They showed numerous irregularly spaced varicosities, were mostly oriented vertically, and in rare cases gave rise to boutons terminaux as they ascended toward the pial surface. At the border between layers I and II, they branched into horizontal fibers that could be followed for several hundred microns in layer I and gave rise to terminal clusters of boutons. In some sections, CGRP-positive fibers were seen in close association with blood vessels. At the electron microscopic level, CGRP immunoreactivity was found in axon terminals containing few mitochondria and clear synaptic vesicles. CGRP-positive axon terminals were very sparse, and mainly of small size. The majority formed conventional synapses, all of the asymmetric type. CGRP-positive fibers showed an uneven topographic distribution through the cortical mantle, with the frontal areas exhibiting the highest density and the occipital cortex the lowest. These results show that CGRP-containing axons are more widely distributed than previously thought since they were observed in all the cortical areas examined, and cast some doubts on the hypothesis that the functional role of this peptide is restricted to the processing of visceral sensory information.(ABSTRACT TRUNCATED AT 250 WORDS)

Download full-text PDF

Source
http://dx.doi.org/10.1093/cercor/4.1.97DOI Listing

Publication Analysis

Top Keywords

cgrp-positive fibers
12
calcitonin gene-related
8
gene-related peptide
8
peptide cgrp
8
topographic distribution
8
cgrp immunoreactivity
8
electron microscopic
8
microscopic level
8
axon terminals
8
fibers
6

Similar Publications

We demonstrated previously that sorting nexin 25 (SNX25) in nerve-associated macrophages plays critical roles in pain sensation by regulating tissue NGF content under both physiological and neuropathic conditions. In the present study, we apply the SNX25-NGF paradigm to tactile perception by showing that Snx25 mice or macrophage-specific Snx25 conditional knock-out (mcKO) mice had weaker responses to tactile stimuli in normal conditions. Snx25 mcKO mice responded poorly to transcutaneous electrical stimuli at a frequency of 5 Hz (C fiber responses), but normally to stimuli at a frequency of 250 Hz (Aδ fiber responses) or of 2000 Hz (Aβ fiber responses).

View Article and Find Full Text PDF

Breast cancer is one of the leading causes of mortality among women. The tumour microenvironment, consisting of host cells and extracellular matrix, has been increasingly studied for its interplay with cancer cells, and the resulting effect on tumour progression. While the breast is one of the most innervated organs in the body, the role of neurons, and specifically sensory neurons, has been understudied, mostly for technical reasons.

View Article and Find Full Text PDF

Netrin-1 Role in Nociceptive Neuron Sprouting through Activation of DCC Signaling in a Rat Model of Bone Cancer Pain.

J Integr Neurosci

February 2024

Department of Anesthesiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, School of Medicine, 200030 Shanghai, China.

Background: Bone cancer pain (BCP) is a common primary or metastatic bone cancer complication. Netrin-1 plays an essential role in neurite elongation and pain sensitization. This study aimed to determine the role of netrin-1 from the metastatic bone microenvironment in BCP development and identify the associated signaling pathway for the strategy of BCP management.

View Article and Find Full Text PDF

Characterization of sensory and motor dysfunction and morphological alterations in late stages of type 2 diabetic mice.

Front Endocrinol (Lausanne)

March 2024

Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing, China.

Diabetic neuropathy is the most common complication of diabetes and lacks effective treatments. Although sensory dysfunction during the early stages of diabetes has been extensively studied in various animal models, the functional and morphological alterations in sensory and motor systems during late stages of diabetes remain largely unexplored. In the current work, we examined the influence of diabetes on sensory and motor function as well as morphological changes in late stages of diabetes.

View Article and Find Full Text PDF

Purpose: The prevalence of lower urinary tract symptoms (LUTS), characterized by problems regarding storage and/or voiding of urine, is known to significantly increase with age. Effective communication between the lower urinary tract and the central nervous system (CNS) is essential for the optimal function of this system, and heavily relies on the efficient interaction between the bladder urothelium and the afferent nerve fibers situated in close proximity to the urothelium within the lamina propria.

Methods: We aimed to quantify aging-related differences in the expression of calcitonin gene-related peptide (CGRP, an established marker for sensory nerve fibers) in the trigonal mucosal layers of young (3-4 months) and aged (25-30 months) rats.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!