Intracisternally injected galanin-(1-15) modulates the cardiovascular responses of galanin-(1-29) and the 5-HT1A receptor agonist 8-OH-DPAT

• Published in: European journal of pharmacology Vol. 257; no. 3; pp. 257 - 265
• Main Authors: NARVAEZ, J. A, DIAZ, Z, AGUIRRE, J. A, GONZALEZ-BARON, S, YANAIHARA, N, FUXE, K, HEDLUND, P. B
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 23.05.1994
• Subjects: 8-Hydroxy-2-(di-n-propylamino)tetralin - administration & dosage; 8-Hydroxy-2-(di-n-propylamino)tetralin - pharmacology; Animals; Biological and medical sciences; Blood Pressure - drug effects; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Cisterna Magna; Dose-Response Relationship, Drug; Drug Interactions; Drug Synergism; Fundamental and applied biological sciences. Psychology; Galanin; Heart Rate - drug effects; Male; Neuropeptides - administration & dosage; Neuropeptides - pharmacology; Peptide Fragments - administration & dosage; Peptide Fragments - metabolism; Peptide Fragments - pharmacology; Peptides - administration & dosage; Peptides - pharmacology; Rats; Rats, Sprague-Dawley; Respiration - drug effects; Vertebrates: nervous system and sense organs; Agonist; Galanin; Interaction; Peptide hormone; Neuropeptide; Hypothalamic hormone; Heart rate; Biological fixation; Peptide fragment; Animal; Peptidergic receptor; S1A receptor; Blood pressure; Hemodynamics; Brain (vertebrata)
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/0014-2999(94)90137-6

In view of the demonstration of specific binding sites for [125I]galanin-(1-15) in several brain areas including the nucleus of the solitary tract, possibly indicating the existence of multiple galanin receptor subtypes, the effects of intracisternal injections of galanin-(1-15) on cardiovascular parameters were studied. The effects of co-injections of galanin-(1-15) and galanin-(1-29) and co-injections of galanin-(1-15) and the 5-HT1A receptor agonist 8-OH-2-(di-n-propylamino)tetralin (8-OH-DPAT) were also evaluated. Galanin-(1-15) produced a significant increase in mean arterial blood pressure (maximum effect 10% at 3 nmol of galanin-(1-15)) and in heart rate (maximum effect 12% at 1 nmol). When threshold doses of galanin-(1-15) (0.1 nmol) and galanin-(1-29) (3 nmol) were injected simultaneously they elicited an increase in mean arterial blood pressure. The vasodepressor response induced by an ED50 dose of 8-OH-DPAT (6 nmol) was not modulated by a threshold dose of galanin-(1-15), but the increase in heart rate area induced by galanin-(1-15) alone was no longer observed. When threshold doses of both galanin-(1-15) and 8-OH-DPAT (0.3 nmol) were co-injected a vasodepressor response developed and on heart rate a tachycardic response was seen in the peak effects and the overall tachycardic response induced by galanin-(1-15) was sustained. The results show a different role for galanin-(1-15) as compared with galanin-(1-29) in central cardiovascular control.