Receptor autoradiography of μ and δ opioid peptide receptors in spontaneously hypertensive rats

• Published in: Peptides (New York, N.Y. : 1980) Vol. 12; no. 4; pp. 779 - 785
• Main Authors: Kujirai, Kayoko, Fahn, Stanley, Cadet, Jean Lud
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.1991; Elsevier Science
• Subjects: Animals; Arterial hypertension. Arterial hypotension; Autoradiography; Biological and medical sciences; Blood and lymphatic vessels; Brain - metabolism; Cardiology. Vascular system; Enkephalin, Ala-MePhe-Gly; Enkephalin, D-Penicillamine (2,5); Enkephalins - metabolism; Experimental diseases; Medical sciences; Motor Activity; Opioid receptors; Rats; Rats, Inbred SHR; Rats, Inbred Strains; Receptor autoradiography; Receptors, Opioid - metabolism; Receptors, Opioid, delta; Receptors, Opioid, mu; Spontaneously hypertensive rats; Striatum; Substantia nigra; Tissue Distribution; Ventral tegmental area; Striatum; Spontaneously hypertensive rats; Receptor autoradiography; Opioid receptors; Ventral tegmental area; Substantia nigra; Hypertension; Rat; Opiate receptor δ; Rodentia; Central nervous system; Cardiovascular disease; Binding site; Opioid peptide; Opiate receptor μ; Autoradiography; Vertebrata; Experimental disease; Mammalia; Animal; Brain (vertebrata)
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/0196-9781(91)90133-A

The receptor autoradiographic distribution of opioid peptide receptors in spontaneously hypertensive rats (SHR) was compared to that of Sprague-Dawley (SD) rats, using the highly selective μ and δ opioid receptor ligands, [ 3H]DAGO (Tyr-D-Ala-Gly-NMe-Phe-Gly-ol) and [ 3H]DPDPE ([D-Pen 2,D-Pen 5]enkephalin), respectively. Although the distribution of these binding sites was similar in both strains, SHR showed significantly higher binding densities of μ receptors in 16 of 27 areas examined. These included the patch and matrix components of the caudate-putamen (CPu), olfactory tubercle, endopiriform nucleus, anterior cingulate cortex, ventral tegmental area, lateroposteral thalamic nucleus and the ventral part of the dentate gyrus. In contrast, SHR had lower [ 3H]DAGO binding sites in the CA1 of the hippocampus. Conversely, SHR showed higher binding densities of δ receptors in 7 of 20 areas examined, including the CPu, CA2 and CA3 areas of the hippocampus and the central grey. High-to-low lateromedial gradients of striatal δ receptors were observed in both strains. Because opioid peptides are known to participate in locomotive behavior in rodents and in the control of blood pressure, the present results support a role of opioid peptidergic systems in the manifestation of hyperactivity and hypertension observed in SHR.