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Bombesin Receptors in the Brain
Author(s) -
WOODRUFF G. N.,
HALL M. D.,
REYNOLDS T.,
PINNOCK R. D.
Publication year - 1996
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1996.tb15126.x
Subject(s) - receptor , bombesin , neuroscience , chemistry , biology , biochemistry , neuropeptide
We have shown that in the central nervous system BN receptors are closely associated with 5-HT systems. On a subpopulation of dorsal raphe neurons, NMB receptors are able to depolarize cells by reducing gK+. In one of the target regions of the dorsal raphe 5-HT neurons, the SCN, we have also shown that neurons are excited by BN-related peptides. In the SCN, the GRP receptors excite neurons by two different mechanisms: closure of gK+ and opening of an unidentified cation conductance. Expression of human BN receptors from the brain in CHO cells or Xenopus oocytes shows a very similar pharmacological profile to that seen in the rat brain slice preparations. In the CHO cell line, following BN receptor activation, a major second-messenger path involves hydrolysis of PIP2 by phospholipases to yield IP3, which releases Ca2+ from intracellular stores. In the oocyte expression system, a similar second messenger pathway is clearly apparent, and Ca2+-sensitive gCl- represents the last phase in a cascade of events. The final phase of the mechanism of action in the artificial systems does not involve gK+, suggesting a different second messenger cascade to that in neurons. However, the involvement of phospholipases and their phospholipid products have not been excluded in neurons.