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Expression of histamine receptors and effect of histamine in the rat carotid body chemoafferent pathway
Author(s) -
Lazarov Nikolai,
Rozloznik Miroslav,
Reindl Sebastian,
ReyAres Verónica,
Dutschmann Mathias,
Gratzl Manfred
Publication year - 2006
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2006.05241.x
Subject(s) - glomus cell , carotid body , histamine , histidine decarboxylase , histamine h3 receptor , medulla oblongata , endocrinology , medicine , microinjection , receptor , chemistry , histamine receptor , brainstem , solitary nucleus , medulla , biology , central nervous system , biochemistry , antagonist , histidine , amino acid , stimulation
Chemosensory information from peripheral arterial oxygen sensors in the carotid body is relayed by petrosal ganglion neurons to the respiratory networks in the medulla oblongata. Biogenic amines, including histamine, released from glomus (type I) cells of the carotid body are considered to be primary transmitters in hypoxic chemosensitivity. Immunocytochemistry at light‐and electron‐microscopical levels, and RT‐PCR, revealed the expression of histamine receptors 1 and 3 as well as histidine decarboxylase in the rat carotid body glomus cells and petrosal ganglion neurons. Histamine receptors 1 and 3, but not histidine decarboxylase, were also observed in the ventrolateral, intermediate and commissural subnuclei of the nucleus tractus solitarii in the medulla oblongata. In order to examine the possible role of histamine in the afferent branch of the respiratory system, we applied histamine receptor 1 and 3 agonists to the carotid body, which caused a mildly increased phrenic nerve activity in a working heart–brainstem preparation. Moreover, microinjection of antagonists of histamine receptors 1 and 3 into the nucleus tractus solitarii caused significant changes in the inspiratory timing and the chemoreceptor response. Our data show that histamine acting via histamine receptors 1 and 3 plays an important neuromodulatory role in the afferent control of chemosensitivity.