Properties and Functions of a Neuromedin‐B‐Preferring Bombesin Receptor in Brain Microvascular Endothelial Cells

• Published in: European journal of biochemistry Vol. 233; no. 2; pp. 414 - 418
• Main Authors: Vigne, Paul, Feolde, Eric, Renterghem, Catherine, Breittmayer, Jean Philippe, Frelin, Christian
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 15.10.1995
• Subjects: Animals; blood brain barrier; Bombesin - pharmacology; Brain - metabolism; Calcium - metabolism; Cell Division - drug effects; Cells, Cultured; Endothelium, Vascular - metabolism; intracellular Ca2; Microcirculation - metabolism; Na+, K+, 2C1− cotransporter; Na+/H+ exchange; Neurokinin B - analogs & derivatives; Neurokinin B - pharmacology; phospholipase C; Potassium - metabolism; Rats; Receptors, Bombesin - analysis; Receptors, Bombesin - physiology; Rubidium - metabolism; Type C Phospholipases - metabolism
• ISSN: 0014-2956; 1432-1033
• DOI: 10.1111/j.1432-1033.1995.414_2.x

Endothelial cells were isolated from rat brain microvessels and grown in vitro. They expressed a high density of [125I‐Tyr4]bombesin receptors (Bmax= 0.9 pmol/mg protein) with an apparent Kd value of 10nM. The pharmacological profile of inhibition of the specific [125I‐Tyr4]bombesin binding [bombesin = neuromedin B > gastrin releasing peptide (GRP)] was consistent with the presence of a neuromedin‐B‐preferring receptor. Addition of bombesin, neuromedin B and GRP increased the activity of phospholipase C as measured by the production of total inositol phosphates and from intracellular Ca2+ measurements. They increase 86Rb4 uptake by the Na+, K+, 2C1− cotransporter and by a charybdotoxin‐sensitive, Ca2+‐activated K+ channel and 22Na+ uptake by the Na+/H+ exchanger. The pharmacological profiles of activation of phospholipase C., Na+, K+, 2C1 cotransport and Na+/H+ exchange by bombesin‐like peptide were consistent with an involvement of the neuromedin‐B‐preferring receptor characterized in binding experiments. It is suggested that one of the actions of neuromedin B in brain vessels could be to control K+ secretion by the blood/brain barrier.