Mast cells in the brain: Possibilities for physiological psychology

Abstract

Recent studies have demonstrated the presence of large numbers of mast cells (MCs) or similar cytological elements within the meninges and within perivascular tissue of brains from many mammalian species. The distributions of MCs within brain space appear to be a function of species, age, and possibly experience. Dense cytoplasmic granules within brain MCs appear to contain heparin, histamine, serotonin (in some species), protein complexes, and sulfomucopolysaccharides. MCs may account for almost all the histamine in the neonatal rat brain and up to 70% of this amine 's content in the adult rat brain. The topographical, morphological, pharmacological, and immunological properties of MCs suggest their involvement in processes of interest to physiological psychologists. Detailed information concerning brain MC characteristics as well as possibilities for their functions are presented.Mast cells (MCs), which may contain significant amounts of histamine, have been found within brain space. These cells have been considered to be longlived, mobile components of connective tissue (Bloom & Fawcett, 1968; Copenhaver, Bunge, & Bunge, 1971), but may compose a functionally independent intraorganismic system and only share the same space as the connective tissue matrix (Csaba, 1972). Abundant numbers of MCs are found typically around blood vessels and within the lung, uterus, spleen, liver, kidney, and heart. During disease conditions, anistropic concentrations of MCs may occur within many places, such as in lymphatic tissue.Classical (nonneural) mast cells display densely granulated cytoplasmic patterns similar to that of the basophilic leukocyte in the blood. The granules contain sulfomucopolysaccharides like heparin (best known for its anticoagulation properties) to which the histamine is bound (Uvnas, 1974) as well as protein complexes, lipids, the ground substances hyaluronic acid or chondroitin sulfate (Watanabe, Watanabe, Ohishi, Aiba, & Kageyarna, 1974) and possibly serotonin in some species. When stained with thionin and toluidine blue in appropriate pH solutions , these granules demonstrate y metachromatic reactions (Kiernan, 1976)typified by pinkpurplish red colorations, whereas the cytoplasmic elements of other cells stain blue. In vitro and in vivo studies have demonstrated that these biopotent granules may be retained in the cell indefinitely or may be released explosively in response to a variety of chemical and mechanical stimuli. An excellent text on nonneural MCs has been prepared by Selye (1965). MAST CELLS IN THE CENTRAL NERVOUS SYSTEM Characteristics and MethodologyTraditionally, MCs have been regarded as virtually absent from the parenchyma of the CNS under normal conditions. Mast cells have been reported in the periphery of infarcts, around or within plaques associated with multiple sclerosis and in the vascular portions of syphilitic lesions of the human brain (Olsson, 1968), but these cases have been considered exceptional. However, accumulating evidence by Cammermeyer (1972Cammermeyer ( , 1973, Ca...

Stimuli from Conspecifics Influence Brain Mast Cell Population in Male Rats

“…We concentrated on the diencephalon as previous reports indicated that in unstimulated rats, brain mast cells occur mainly in the dorsal thalamic nuclei, although some are also found in the leptomeninges, olfactory bulb, hypothalamus, and mesencephalon (Dropp, 1976;Persinger, 1977;Ibrahim, Wirr, and Bahuth, 1979;Goldschmidt et al, 1984;Theoharides, 1996).…”

Brain and Spinal Cord Levels of Histamine in Lewis Rats with Acute Experimental Autoimmune Encephalomyelitis

“…On the other hand, histochemical and immunohistochemical studies have clearly demonstrated the presence of mast cells within (thalamus and hypothalamus) and close to (dorsal root ganglia and dura mater) the CNS (Selye et al, 1963;Olsson, 1968;Dropp, 1976;Persinger, 1977;Panula et al, 1984;Steinbusch andMulder, 1984, 1985;Hough et al, 1985;Panula, 1986;Orr, 1988). Moreover, the vast majority of these CNSassociated mast cells are found in close proximity to blood vessels and the subarachnoid space.…”

Elevated Concentrations of Histamine in the Rat Brain

“…SCHWARTZ and his collaborators (see SCHWARTZ, 1976 andMARTRES, et al, 1975) have accumulated evidence that H m is found in a neuronal and a non-neuronal pool in rat brains, and have suggested that the non-neuronal pool may be in mast cells. In addition, other investigators (DROPP, 1972;IBRAHIM, 1974;KRUGER, 1974;PERSINGER, 1977) have found, in the CNS of rats and other vertebrates, cells that are morphologically similar to mast cells. Thus, one possibility is that the 'extra' H m is found in mast cells or mast cell-like cells, and these cells may be more difficult to disrupt and quantitatively extract for H m than are neurons.…”