Central effects of various ligands on drinking behavior in eels acclimated to seawater.

Intracranial injection of eel angiotensin II (eANG II, 5x10(-13)-5x10(-8) mol), acetylcholine (ACh, 5x10(-12)-5x10(-9) mol), substance P (5x10(-10) mol) and isoproterenol (a beta-adrenoceptor agonist, 5x10(-11)-5x10(-9) mol) enhanced water intake in the seawater eel. The effects of eANG II, ACh and isoproterenol were dose-dependent. By contrast, water intake was inhibited by intracranial injection of eel atrial natriuretic peptide (eANP, 5x10(-13)-5x10(-10) mol), serotonin (5-HT, 5x10(-12)-5x10(-8) mol), ghrelin (5x10(-12)-5x10(-10) mol), gamma-amino butyric acid (GABA, 5x10(-11)-5x10(-8) mol), prolactin (PRL, 5x10(-10)-5x10(-9) mol), arginine vasotocin (AVT, 5x10(-12) mol), vasoactive intestinal peptide (VIP, 5x10(-11) mol), noradrenaline (5x10(-9) mol l(-1)) and phenylephrine (alpha-adrenoceptor agonist, 5x10(-11)-5x10(-9) mol).