ABSTRACT
In tests of "illuminated area" and the "threatening situation" avoidance by rats, apomorphine and phenamine, administered intraperitoneally, attenuate the state of alarm. A similar effect is observed when sulpiride, a selective blocker of D2-receptors of dopamine, and of picrotoxin, a GABA antagonist, are administered. Sulpiride effectively counteracts the anxiolytic effects of all of the dopaminomimetics investigated and of picrotoxin. Haloperidol, a nonselective blocker of the D1- and D2-receptors of dopamine removes the anxiolytic effect of apomorphine, phenamine, and picrotoxin. The microinjection into the ventral region of the midbrain tegmentum of dopamine, or of sulpiride into the nucleus accumbens of the septum, attenuates the state of alarm formed by aversive influences of various biological modalities. By contrast, sulpiride, introduced locally into the tegmentum, or chemical stimulation of the nucleus accumbens of the septum by dopamine, intensifies the state of alarm in the "illuminated area" avoidance test. The participation of dopaminergic mechanisms of the mesolimbic system of the brain in anxiety of various aversive causations is discussed.
Subject(s)
Anxiety/physiopathology , Brain/physiopathology , Dopamine/physiology , Animals , Brain Chemistry/drug effects , Dopamine/pharmacology , Dopamine Agonists/pharmacology , Dopamine Antagonists/pharmacology , GABA Antagonists/pharmacology , Male , Microinjections , Motor Activity/drug effects , Muscle Relaxants, Central/pharmacology , Rats , Receptors, Dopamine D1/agonists , Receptors, Dopamine D1/antagonists & inhibitorsSubject(s)
Anxiety/physiopathology , Brain/physiopathology , Receptors, Dopamine/physiology , Animals , Anxiety/chemically induced , Brain/drug effects , Disease Models, Animal , Dopamine Agents/pharmacology , Dopamine Antagonists , GABA Antagonists , Male , Microinjections/methods , Rats , Receptors, Dopamine/drug effectsABSTRACT
Microinjections of monoamines and amino acids into rat ventral hippocampus showed functional relevance of GABA- or dopamine- and 5-HT-ergic mechanisms of this structure of brain formed by aversive actions of diverse biological importance rather than glutamate-ergic ones. The participation of hippocampus monoamine- and acidergic mechanisms in the origin of diverse aversive anxiety is discussed.
Subject(s)
Anxiety/etiology , Avoidance Learning/physiology , Hippocampus/physiology , Animals , Anxiety/physiopathology , Avoidance Learning/drug effects , Dopamine/administration & dosage , Glutamates/administration & dosage , Glutamic Acid , Hippocampus/drug effects , Male , Microinjections , Rats , Serotonin/administration & dosage , gamma-Aminobutyric Acid/administration & dosageABSTRACT
In experiments on rats the presence or absence was studied of the phenomenon of potentiation of anxiolytic action, estimated by the time of the animal stay in the light part of the chamber in tests of avoidance of "the lighted ground" or "menacing situation" at combined application of the pairs of substances of benzodiasepine and non-benzodiasepine series (elenium, indoter, campiron and campironin). Spectra of their neurochemical activity were determined in experiments on neurones of isolated spinal ganglia of rats with intracellular biopotentials records. It has been established that GABA-potentiating action of indoter and elenium, dopamine-negative action of campiron and campironin are significant in their anxiolytic action in the states of alarm of aversive genesis of different modalities. Serotoninmimetic effect of non-diasepine tranquilizers is of functional significance in the test of avoidance of "the lighted ground", but not of the "menacing situation". It is suggested that differences of neurochemical mechanisms of anxiolytic action of the tested tranquilizers testify to different neurochemical profiles of the neuronal "matrices" of the studied states of alarm.
