Calcitonin gene-related peptide (CGRP) in the nipple of the rat mammary gland

TY - JOUR

T1 - Calcitonin gene-related peptide (CGRP) in the nipple of the rat mammary gland

AU - Thulesen, J

AU - Rasmussen, T N

AU - Schmidt, P

AU - Holst, J J

AU - Poulsen, Steen Seier

PY - 1994/12

Y1 - 1994/12

N2 - The distribution of nerve fibres immunoreactive to calcitonin gene-related peptide (CGRP) was investigated by immunohistochemistry in nipples and mammary glands from lactating and non-lactating rats and compared to the immunoreactivity of other neuropeptides including substance P (SP), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and somatostatin (SOM). The study revealed an extensive innervation of the mammary nipples, in which CGRP-immunoreactive (IR) nerve fibres were abundantly present in the epidermis, dermal connective tissue and intralobular connective tissue of the mammary gland parenchyma. Several of the dermal CGRP-IR fibres seemed to follow blood vessels, or formed "ringlet-like" structures. The latter were mostly observed in the dermal connective tissue of the nipple from the lactating rat and may have a mechanoreceptive function, e.g. for the suckling stimuli. The location of SP-IR appeared to be comparable to CGRP-IR, but in fewer fibres. Dense NPY-IR networks of nerve fibres were closely associated with the fascicles of smooth musculature in the core of the nipple base. In contrast, VIP-IR fibres were only sparsely present, and SOM-IR was not detected in the mammary nipples. The immunoreactive content of CGRP and SP was determined by radioimmunoassays. The total amount of immunoreactive CGRP was significantly higher in the nipples from the pregnant and the lactating rats when compared to SP. The maximum concentration of CGRP (65.9 +/- 4.0 pmol/g) measured in the nipples of the pregnant (day 10) rats exceeded almost ninefold the maximum concentration of SP (7.7 +/- 2.0 pmol/g).(ABSTRACT TRUNCATED AT 250 WORDS)

AB - The distribution of nerve fibres immunoreactive to calcitonin gene-related peptide (CGRP) was investigated by immunohistochemistry in nipples and mammary glands from lactating and non-lactating rats and compared to the immunoreactivity of other neuropeptides including substance P (SP), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and somatostatin (SOM). The study revealed an extensive innervation of the mammary nipples, in which CGRP-immunoreactive (IR) nerve fibres were abundantly present in the epidermis, dermal connective tissue and intralobular connective tissue of the mammary gland parenchyma. Several of the dermal CGRP-IR fibres seemed to follow blood vessels, or formed "ringlet-like" structures. The latter were mostly observed in the dermal connective tissue of the nipple from the lactating rat and may have a mechanoreceptive function, e.g. for the suckling stimuli. The location of SP-IR appeared to be comparable to CGRP-IR, but in fewer fibres. Dense NPY-IR networks of nerve fibres were closely associated with the fascicles of smooth musculature in the core of the nipple base. In contrast, VIP-IR fibres were only sparsely present, and SOM-IR was not detected in the mammary nipples. The immunoreactive content of CGRP and SP was determined by radioimmunoassays. The total amount of immunoreactive CGRP was significantly higher in the nipples from the pregnant and the lactating rats when compared to SP. The maximum concentration of CGRP (65.9 +/- 4.0 pmol/g) measured in the nipples of the pregnant (day 10) rats exceeded almost ninefold the maximum concentration of SP (7.7 +/- 2.0 pmol/g).(ABSTRACT TRUNCATED AT 250 WORDS)

KW - Animals

KW - Calcitonin Gene-Related Peptide

KW - Female

KW - Immunohistochemistry

KW - Lactation

KW - Mammary Glands, Animal

KW - Nerve Fibers

KW - Neuropeptide Y

KW - Nipples

KW - Radioimmunoassay

KW - Rats

KW - Rats, Wistar

KW - Somatostatin

KW - Substance P

KW - Vasoactive Intestinal Peptide

M3 - Journal article

C2 - 7535296

SN - 0301-5564

VL - 102

SP - 437

EP - 444

JO - Histochemistry

JF - Histochemistry

IS - 6

ER -