Histamine and the Blood

A role for mast cells in adenosine A3 receptor‐mediated hypotension in the rat

“…Finally, hypotensive responses to both APNEA and compound 48/80 are associated with substantial increases in plasma histamine. Taken together, the data implicate the mast cell in a key role in A3 receptormediated hypotension and are entirely consistent with the fact that rat mast cells express the A3 receptor and are activated by ligands with A3 receptor agonist properties in vitro (Ali et al, 1990;1991;Ramkumar et al, 1993).…”

“…The data are presented in Table 1. The concentrations of histamine measured in plasma and serum in vehicle-treated animals were close to the standard values reported earlier for these tissues by several authors (see review by Tasaka, 1991). (Figure 3a).…”

“…Indeed, it is unknown whether APNEA acts directly on elements of the cardiovascular system or indirectly by inducing transmitter or mediator release. With respect to the latter, a plausible candidate for an intermediary role is the mast cell, which has been shown to express the A3 receptor (Ali et al, 1990;1991;Ramkumar et al, 1993) and to be activated by ligands with A3 receptor agonist properties (Ramkumar et al, 1993). Significantly, both the biochemical events and facilitation of mediator release induced by A3 receptor-mediated activation of mast cells are pertussis toxinsensitive (Ali et al, 1990;Qian & McCloskey, 1993 present experiments were designed to explore the role of mast cells in the hypotensive responses induced by A3 receptor activation in the rat.…”

Effects of the neuropeptide Y Y1 receptor antagonist SR 120107A on sympathetic vascular control in pigs in vivo

“…But splenic venous and arterial plasma histamine levels were unchanged in its presence. However, basal plasma levels in the pig tend to be very high (Tasaka 1991) and seem to vary among individual pigs. Hence, for a more conclusive analysis of this matter another species than the pig could be more favourable.…”

Induction of the activity of the histamine-forming enzyme, histidine decarboxylase, in mice by IL-18 and by IL-18 plus IL-12

“…Histamine has also been shown to modulate a variety of immune responses in vitro, including the production of cytokines, the activities of T cells, NK cells, granulocytes and macrophages and the proliferation of haematopoietic precursor cells [1,2,61]. Histamine also has an anti-tumour action against some tumour cells in vivo (via the stimulation of H2 receptors on NK cells) [62].…”