Distribution and subtype determination of beta-receptors in the spinal cord of the adult rat

• Published in: Cellular and molecular neurobiology Vol. 9; no. 4; pp. 461 - 468
• Main Authors: Schrader, E, Grobecker, H
• Format: Journal Article
• Language: English
• Published: United States 01-12-1989
• Subjects: Adenylyl Cyclases - metabolism; Animals; Atenolol - metabolism; Binding, Competitive; Dihydroalprenolol - metabolism; Isoproterenol - pharmacology; Male; Practolol - metabolism; Propranolol - metabolism; Rats; Rats, Inbred Strains; Receptors, Adrenergic, beta - analysis; Receptors, Adrenergic, beta - metabolism; Spinal Cord - analysis; Spinal Cord - metabolism
• ISSN: 0272-4340
• DOI: 10.1007/BF00712793

1. We determined the number of beta-receptors in the whole spinal cord of the adult rat and in the cervical, thoracal, and lumbal/sacral parts. 2. The undivided spinal cord contains 47 +/- 10 fmol/mg beta-receptors (KD = 2066 +/- 982 pmol/liter), and the cervical part of the spinal cord contains 53 +/- 8 fmol/mg protein (KD = 3224 +/- 1775 pmol/liter). The thoracal part shows 40 +/- 1 fmol/mg protein (KD = 3229 +/- 104 pmol/liter), and the lumbal/sacral spinal cord contains 48 +/- 8 fmol/mg protein (KD = 3610 +/- 1610 pmol/liter). 3. Competitive inhibition studies with l-practolol, dl-atenolol, and ICI 118,551 were performed and we calculated by a computer program in the whole spinal cord the following ratio of beta-receptor subtypes: 80 +/- 5% Beta 1-receptors and 20 +/- 5% beta 2-receptors. 4. The basal and (-)-isoproterenol- and NaF-stimulated activity of adenylate cyclase was highest in the cervical part of the spinal cord and equally distributed between the thoracal and the lumbal/sacral parts. 5. The whole synaptosomal protein of the cervical part of the spinal cord contained 132 +/- 20 fmol, the thoracal part 117 +/- 3 fmol, and the lumbal/sacral part 133 +/- 22 fmol.