Background Neurotrophin-3 (NT-3) is produced by astrocytes, in addition to neurons, and monoamine neurotransmitters play a role in controlling NT-3 synthesis [1]. The impact of histamine on the regulation of NT-3 synthesis in cultured astrocytes has not been studied in detail. Therefore, we focused our present study on the active involvement of multiple histaminergic receptor and intracellular ...

Prostaglandin (PG)E2 promotes the wakeful state when administered into the posterior hypothalamus, in which the histaminergic tuberomammillary nucleus (TMN) is located. To explore the neurotransmitter mechanisms responsible for PGE2-induced wakefulness in rats, we examined the effect of PGE2 on the activity of the histaminergic system and the involvement of PGE2 receptor subtypes in the respons...

Feeding behavior is regulated by a complex interplay of many endogenous substances, such as peptides and neurotransmitters in the central nervous system. Histamine is a neurotransmitter which expresses an anorectic effect on food intake via histamine H(1) receptors. The histaminergic system exists downstream of leptin, a satiety factor secreted from white adipose tissue. Because direct stimulat...

The human histaminergic system contains approximately 64.000 neurons located in a posterior region of the hypothalamus, the tuberomamillary nucleus. Projections of such a relatively small number of neurons are surprisingly widespread throughout the central nervous system. Histaminergic neurons are highly active during wakefulness and contribute to the physiology of arousal state, exploration, p...

The tuberomammillary (TM) nuclei of the hypothalamus appear to be the sole histaminergic cell group in the brain. The extracellular electrophysiological properties of cortically projecting TM neurons were studied in the urethane-anesthetized rat. TM neurons, antidromically activated from either ipsi- or contralateral cerebral cortex, displayed relatively slow conduction velocities, consistent w...

Background Neurotrophin-3 (NT-3) is produced by astrocytes, in addition to neurons, and monoamine neurotransmitters play a role in controlling NT-3 synthesis [1]. The impact of histamine on the regulation of NT-3 synthesis in cultured astrocytes has not been studied in detail. Therefore, we focused our present study on the active involvement of multiple histaminergic receptor and intracellular ...

(1) The pharmacology of ATP responses and the expression pattern of seven known subunits of the P2X receptor were investigated in individual histaminergic neurons of the tuberomamillary nucleus (TM). (2) ATP (3-1000 micro M) evoked fast non-desensitizing inward currents in TM neurons. 2-methylthioATP (2MeSATP) displayed the same efficacy but a lower potency, EC(50)s 84 micro M versus 48 micro M...

The histaminergic tuberomamillary nucleus (TMN) controls arousal and attention, and the firing of TMN neurons is state-dependent, active during waking, silent during sleep. Thyrotropin-releasing hormone (TRH) promotes arousal and combats sleepiness associated with narcolepsy. Single-cell reverse-transcription-PCR demonstrated variable expression of the two known TRH receptors in the majority of...

Release of arachidonic acid from membrane phospholipids is receptor-mediated and might generate second messengers in neurons. We tested this idea using the simple nervous system of the marine mollusk, Aplysia californica. Aplysia neural components metabolize arachidonic acid through lipoxygenase and cyclo-oxygenase pathways. We identified 2 major lipoxygenase products, 12- and 5-hydroxyeicosate...