Benzodiazepines and putative 5-HT1A agonists increase hypertonic saline consumption in rehydrating rats.
Male rats were adapted to a 22 hr water-deprivation schedule, and to a 30 min test of hypertonic (1.8 or 2.7%) NaCl solution ingestion. A novel benzodiazepine, Ro23-0364, recently reported to have anxiolytic activity in rats and squirrel monkeys but to have limited potential to produce unwanted side effects, produced significant dose-related increases in hypertonic saline ingestion. Midazolam, a benzodiazepine full agonist, increased salt intake but the effect was offset at higher doses by the induction of sedation. Three putative 5-HT1A agonists, proposed as nonbenzodiazepine-related anxiolytics, were also tested: the highly selective 8-OH-DPAT, gepirone and ipsapirone (TVX Q 7821). In each case, occasions when hypertonic saline consumption was significantly increased were detected. At 300 micrograms/kg of 8-OH-DPAT and 10 mg/kg of gepirone, the appearance of a pronounced flattened body posture effectively interfered with drinking responses. It appears possible that a behavioural action shared by benzodiazepines and 5-HT1A agonists may be responsible for the increased hypertonic saline ingestion.
Cooper
S J
SJ
Department of Psychology, University of Birmingham, U.K.
Desa
A
A
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D014151:Anti-Anxiety Agents; D001569:Benzodiazepines / Q000494:pharmacology*; D004326:Drinking / Q000187:drug effects; D008297:Male; D008874:Midazolam / Q000494:pharmacology*; D009281:Naphthalenes / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects; D011985:Receptors, Serotonin / Q000187:drug effects; D012462:Saline Solution, Hypertonic / Q000008:administration & dosage*; D012646:Self Administration; D012965:Sodium Chloride / Q000008:administration & dosage*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*
D014151:Anti-Anxiety Agents; D009281:Naphthalenes; D011743:Pyrimidines; D011963:Receptors, GABA-A; D011985:Receptors, Serotonin; D012462:Saline Solution, Hypertonic; D013764:Tetrahydronaphthalenes; D001569:Benzodiazepines; D012965:Sodium Chloride; C043077:ipsapirone; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C039979:gepirone; D008874:Midazolam; C053272:Ro 23-0364