Development of histamine‐immunoreactive neurons in the rat brain

Abstract

This study was undertaken to reveal the cellular stores of histamine in developing rat brain and to determine the stage of development during which the histamine-immunoreactive neurons can first be detected. Rats from embryonal day 12 to postnatal day 14 were studied. The brains were fixed in 4% 1-ethyl-3(3-dimethylaminopropyl)carbodiimide and standard immunofluorescence technique was used. The first histamine-immunoreactive neurons were seen on embryonic day 13 in the border of mesencephalon and metencephalon. On embryonic day 15 immunoreactive neurons were detected in ventral mesencephalon and rhombencephalon. In caudal, tuberal, and postmammillary caudal magnocellular nuclei histamine-immunoreactive neurons were first detected on embryonic day 20 while those in the hindbrain had disappeared. Histamine-immunoreactive nerve fibers were first detected on embryonic day 15 in rhombencephalon and mesencephalon and in some areas of diencephalon including the mammillary bodies and frontal cortex. On embryonic day 18 the number of immunoreactive nerve fibers in the hindbrain had decreased considerably, but the olfactory bulb, septal and hypothalamic area, and the cerebral cortex showed immunoreaction in fibers. The density of histamine-immunoreactive fiber networks increased until postnatal day 14 when an adultlike pattern of neurons and fibers had developed. Histamine-immunoreactive neurons are present in embryonal CNS and they develop extensive projections to various brain areas.

International Union of Basic and Clinical Pharmacology. XCVIII. Histamine Receptors

“…From embryonic day 17, strong expression is found in superficial layers of the cortical plate and ventral hypothalamus. It is noteworthy that in rodents there is a distinct transient fetal histaminergic system in the raphe neurons (Auvinen and Panula, 1988;Vanhala et al, 1994), which implies that the fetal expression of H 2 receptor mRNA may be functional during brain development.…”

In situ detection of H1-receptor mRNA and absence of apoptosis in the transient histamine system of the embryonic rat brain

“…This phenomenon reflects a dramatic decrease of histamine concentration in the pontine region and the disappearance of the transient histamine system by E20 (Vanhala et al, 1994). The appearance of histaminecontaining mast cells in the developing brain starting at E18 (Auvinen and Panula, 1988) and continuing postnatally, results largely in another peak in brain histamine concentration on the fifth postnatal day (P5; Pearce and Schanberg, 1969;Ferrer et al, 1979;Tuomisto and Panula, 1991), whereafter the concentration decreases to that of adult levels during the first postnatal weeks. These mast cells undergo significant phenotypic changes during development (Dimitriadou et al, 1996) and migrate from pial surface to thalamic nuclei (Lambracht-Hall et al, 1990).…”

“…Between E14 and E18, histamine-ir nerve fibers originating from the transient histamine-ir cell group in the raphe nuclei can be transiently detected in the pons, traversing through the ventral tegmental area and within the median forebrain bundle and prominently in the optic tract (Auvinen and Panula, 1988;Vanhala et al, 1994). The first histaminergic nerve fibers reach the frontal and the parietal cortex also very early, at E15 (Auvinen and Panula, 1988), which is earlier than in other monoaminergic systems (Specht et al, 1981;Lidov and Molliver, 1982). Adult-like distribution of the histamine-ir nerve fibers in the developing brain is reached by P14 (Panula et al, 1989(Panula et al, , 1992.…”

Structure of Monoaminergic Neuron Systems in the Brain

“…In the brain of the river lamprey, besides the neurons in the posterior hypothalamus, another group of histamineimmunoreactive neurons exist in the border area between the mesencephalon and rhombencephalon [21]. However, transient appearance of histamineimmunoreactive neurons in the lower brainstem of the rat embryo was reported [22]. Therefore, the histamine containing neurons in the lower brainstem might appear transiently in the developing brains of jawed vertebrates.…”