Histamine

Pharmaceutical

Pharmaceuticals -> Listed in ZINC15

-0.70

-0.7

COLORLESS LONG PRISMATIC CRYSTALS; ODORLESS; 1 G SOL IN ABOUT 4 ML WATER; AQ SOLN IS ACID TO LITMUS; WHEN DRIED AT 105 °C FOR 2 HR, IT MELTS AT ABOUT 140 °C /PHOSPHATE/

FREELY SOL IN WATER, ALCOHOL, HOT CHLOROFORM; SPARINGLY SOL IN ETHER

14.1 [ug/mL] (The mean of the results at pH 7.4)

83-84 °C

86 °C

This chemical does not meet GHS hazard criteria for 6.7% (3 of 45) of reports.

Danger

H301 (93.3%): Toxic if swallowed [Danger Acute toxicity, oral]

P233, P260, P261, P264, P264+P265, P270, P271, P272, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P319, P321, P330, P332+P317, P333+P317, P337+P317, P342+P316, P362+P364, P403, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 45 reports by companies from 5 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

INHIBITORY EFFECT OF METHAMIDE (POTENT H2 ANTAGONIST) ON GASTRIC ACID SECRETION ELICITED BY CONTINUOUS HISTAMINE IV INFUSION IN MAX EFFECTIVE DOSE (20 UMOLE/HR) IN DOGS IS SHOWN TO BE APPROX 20%/10 UMOLE/KG AFTER 1.5 HR. COMPARABLE EFFECTS WERE OBSERVED IN NORMAL HUMANS IN SAME STUDY. /H2-RECEPTOR ANTAGONISTS, FROM TABLE/

IN GUINEA PIGS, DEATH BY ASPHYXIA FOLLOWS QUITE SMALL DOSES OF HISTAMINE, YET ANIMAL MAY SURVIVE A HUNDRED LETHAL DOSES OF HISTAMINE IF GIVEN AN H1-BLOCKING DRUG. IN SAME SPECIES, H1 ANTAGONISTS OFFER STRIKING PROTECTION AGAINST ANAPHYLACTIC BRONCHOSPASM, BUT THIS IS NOT SO IN MAN... /H1-RECEPTOR ANTAGONISTS/

OCCURS WIDELY IN NATURE AS A RESULT OF PUTREFACTIVE PROCESSES.

.../HISTAMINE/ IS A NATURAL CONSTITUENT OF BODY. ... LIBERATED FROM CELLS OF SKIN BY INJURIOUS STIMULI.../&/ INVOLVED IN MANY... DIVERSE PHYSIOLOGICAL PROCESSES...HISTAMINE RECEPTORS...FALL INTO 2 BROAD CLASSES: H1 & H2...

Histamine acts directly on the blood vessels to dilate arteries and capillaries; this action is mediated by both H 1- and H 2-receptors. Capillary dilatation may produce flushing of the face, a decrease in systemic blood pressure, and gastric gland secretion, causing an increased secretion of gastric juice of high acidity. Increased capillary permeability accompanies capillary dilatation, producing an outward passage of plasma protein and fluid into the extracellular spaces, an increase in lymph flow and protein content, and the formation of edema. In addition, histamine has a direct stimulant action on smooth muscle, producing contraction if H 1-receptors are activated, or mostly relaxation if H 2-receptors are activated. Also in humans, the stimulant effect of histamine may cause contraction of the intestinal muscle. However, little effect is noticed on the uterus, bladder, or gallbladder. Histamine has some stimulant effect on duodenal, salivary, pancreatic, bronchial, and lacrimal glands. Histamine also can bind to H3 and H4 receptors which are involved in the CNS/PNS neurotransmitter release and immune system chemotaxis, respectively.

...CONTRACTS MANY SMOOTH MUSCLES, SUCH AS...BRONCHI & GUT, BUT...RELAXES OTHERS...OF FINE BLOOD VESSELS. IT IS...POTENT STIMULUS TO GASTRIC ACID PRODUCTION & ELICITS...OTHER EXOCRINE SECRETIONS. ...BRONCHOCONSTRICTION & CONTRACTION OF GUT...INVOLVE H1 RECEPTORS...GASTRIC SECRETION...INVOLVE ACTIVATION OF H2 RECEPTORS...

...AT CELLULAR LEVEL, MANY RESPONSES TO HISTAMINE ARE CLEARLY ATTRIBUTABLE TO INCR IN MEMBRANE PERMEABILITY THAT ALLOWS COMMON INORG IONS (MAINLY CATIONS) TO FLOW DOWN ELECTROCHEM GRADIENTS & ALTER TRANSMEMBRANE POTENTIAL. IT DOUBTLESS EXPLAINS STIMULANT ACTIONS...OF HISTAMINE ON NERVE ENDINGS OR GANGLION CELLS...

...ESSENTIALLY SIMILAR ACTION /TO THAT AT CELLULAR LEVEL/ APPEARS TO ACCOUNT FOR SECRETION, AT LEAST AS IT OCCURS IN CHROMAFFIN CELLS OF ADRENAL MEDULLA. HERE HISTAMINE...MIMIC PHYSIOLOGICAL SECRETAGOGUE ACH IN DEPOLARIZING THE PLASMALEMMA.