Serotonin (5-HT) regulates aggressive behavior via binding to its receptors, such as 5-HT1A and 1B, in humans and rodents. Here we investigate the heritable components of 5-HT regulation of aggressiveness in chickens, utilizing 3 distinct genetic strains. In this study, we used 2 divergently selected strains (high and low group productivity and survivability, respectively; HGPS and LGPS) and a ...

In this study we examined the effects of 5-HT1A ligands in rats trained to discriminate 0.16 mg/kg i.p. 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) from saline in a two-lever, fixed ratio (FR)10 schedule of food reinforcement, and in pigeons trained to discriminate 0.31 mg/kg i.m. 8-OH-DPAT from saline in a two-key, FR30 schedule of food reinforcement. In both species, 8-OH-DPAT and a va...

The nucleus of solitary tract (NTS) contains diverse neural circuits responsible for basic vital functions. We examined the effect of serotonin (5-HT) on hyperpolarization-activated current (I(h)) in neurons acutely isolated from caudal, medial and rostral parts of the NTS. Caudal and medial NTS neurons showed a large amplitude of I(h) compared with rostral neurons. In these neurons, perfusion ...

Selective activation of the 5-HT1A receptor induces lower lip retraction (LLR) in rats. 8-Hydroxy-dipropylamino tetralin (8-OH-DPAT)-induced LLR could not be antagonised by the 5-HT antagonists methysergide, metergoline or mesulergine. In fact, some 5-HT antagonists induced LLR. However, 8-OH-DPAT-induced LLR could be antagonised by pindolol, spiperone, spiroxatrine and NAN-190, but not by the ...

The effect of blockade of 5-HT1A receptors was investigated on (1). retention in a mildly aversive passive-avoidance task, and (2). spontaneous single-unit activity of central nucleus of the amygdala (CeA) neurons, a brain site implicated in modulation of retention. Systemic administration of the selective 5-HT1A antagonist NAN-190 immediately after training markedly-and dose-dependently-facili...

The role of the 5-hydroxytryptamine (5-HT1A) receptors in the rostral ventrolateral medulla (RVLM) on somatosympathetic, baroreceptor, and chemoreceptor reflexes was examined in anesthetized rats. Microinjection of the selective 5-HT1A agonist 8-hydroxy-di-n-propylamino tetralin (8-OH-DPAT) decreased arterial blood pressure and splanchnic sympathetic nerve activity (SNA). Electrical stimulation...

As a means of characterizing the role of 5-hydroxytryptamine (5-HT1A) receptors in learning, a full 5-HT1A receptor agonist, 8-hydroxy-dipropylaminotetralin (8-OH-DPAT), was administered both alone and in combination with two partial agonists (buspirone and 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190)) and a 5-HT1A receptor antagonist (p-MPPI) to rats respond...

Ro 64-6198 [(1S,3aS)-8-(2,3,3a,4,5,6-hexahydro-1H-phenalen-1-yl)-1-phenyl-1,3,8-triaza-spiro[4.5]decan-4-one] was developed as a nonpeptide agonist of nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptors, using bioassays at cloned receptors expressed in cell cultures. We have investigated the actions of Ro 64-6198 at native NOP receptors of the ventrolateral periaqueductal gray (PAG), a cruci...

Recent behavioral studies indicate that conditioned fear response to contextual stimuli is reduced effectively by anxiolytic 5-hydroxytryptame (5-HT)1A agonists. Since the hippocampus seems to play an essential role in associative fear memories evoked by context, it is important to assess the effect of 5-HT1A agonists on pyramidal cell activity in the hippocampus. We examined the effects of 5-H...

The present study investigated whether the serotonergic system is involved in mediating the behavioral effects of corticotropin-releasing hormone (CRH) in juvenile spring chinook salmon, Oncorhynchus tshawytscha. An intracerebroventricular (ICV) injection of CRH induced hyperactivity. The effect of CRH was potentiated in a dose-dependent manner by the concurrent administration of the serotonin ...