Bombesin: Central nervous system actions to affect the autonomic nervous system

Bombesin: Central nervous system actions to affect the autonomic nervous system

• Bloom S R, Department of Medici K. stgraduate Medical School, received the name "neuromedin", ma re unique. Both were f i r s t i s o l a t ently ...

81KB Sizes 1 Downloads 120 Views

• Bloom S R, Department of Medici K.

stgraduate Medical School,

received the name "neuromedin", ma re unique. Both were f i r s t i s o l a t ently been shown to have a wider d

been given other names bu porcine spinal cord by

be present in human, pig, cat and ;he entire length of the gastrointe in oesophagus and rectum. Immunor concentrations have been found in ;o bombesin, though s l i g h t l y weaker ecretion.

ord. In addition i t is and pancreas with present in several region y gland. Neuromedin B was g gut hormones and in i t s

contrast neuromedin U has no s i m i l a r i t y in sequence with w bombe )fine smooth muscle contracting agent and also increas eases blood ,unoreactivity was found to vary significantly between species. md in the gastrointestinal tract, being particularly high in t ~as also found in the genitourinary tract, spinal cord and brai i g l i a and hypothalamus.

been found to be a potent euromedin U-like high concentrations were large intestine. Neurome t i c u l a r l y high in the moto

BOMBESIN: TH~AUTONOMIC NERVOUS SYSTEM. 3OMBESIN: CENTRAL NERVOUS SYST~EM ACTIONS TO AFFEC~THE Department Autonomic Physiol~gy Laboratory, Labol Marvin rvin F R. Browr~ Jean Rivier ~ and Laurel Fisher . Sal~ Institute, P.O. B Hicine, UCSD Medical Center, 225 Dickinson St., San Diego, CA 92103, =The Salk Medicine Iciences Center, Tucson, AZ 85724. 8572 B00, La Jolla, CA 92037, 3 Univ. of Arizona Health Scie 85800 system (CNS) nez Bombesin and structurallly related mammalian peptides act within the central nervous ystem activity that results in changes of visceral organ functions. Structu modify autonomic nervous sys bombesin is necessary f ~nstrated =ated that an intact C-terminal decapeptide of bomb~ activity studies have demonstrat~ activity. Bombesin (57-570 pmoles) administered into the th lateral cerebrove generation of biological activit le (3V) or into the cisternum magnun (ic) elicits an incre increase in plasma conce tricle (LV), third ventricle >> norepinephrine. Bombesin-induced elevation of plasr~ )Iasma concentrations trations of epinephrine >> ~ented by icv administration of cholinergic, adrenergic or dopamine recept catecholamines is not prevented ~oles) injected into t enous administration of naloxone. Bcalbesin (5.7 pmoles antagonists or by intravenous :leus of the solitary tract, but not when injected into multiple other bra rostral aspect of the nucleus trations. Bombesin given parenchymal areas, produces ~s dramatic elevations of plasma epinephrine concentration etic nervous system innervation of interscapular brown fat without changi or icy decreases sympathetic ~er visceral organs. sympathetic activity in other ~revented by adrenalecto~ ;eases mean arterial pressure, an effect that is preven B~sin given icy increases Bcmbesin stimulates a decre rease of heart rate that is dependent on decreased sym~~athetic and increas bombes n- induced slowing parasympathetic-cholinergicc innervation of the heart. However, not all the bombesi heart rate could be accounted ited for on the basis of changes of sympathetic and paras)~pathetic innervati of the heart. ha~ involve~ the sear Efforts to evaluate the physiologic significance of endogenous brain bombesin have 4 ]_bombes for a useful receptor antac :agonist. The reported bombesin receptor antagonists, [DPhel2,Leu [[ and [D-Arg l,D-Trp 7,~Leu I~_substance P did not block any of the biological actions of exogeno bcmbesin. The composite CNS actions :ions of bombesin described constitute the mechanisms by b which this pepti inhibits regulatory heat production and oxygen consumption in cold-exposed rats, and the elevation plasma concentrations of glucagon and glucose. A diverse and interesting neurobiology neur( for bombes exists; however, the lack of useful receptor antagonists has retarded the evaluati valuation of the physiolog relevance of this peptide.

102