H1

links: Histamine reference: 9-18-2021

Histamine H1 Receptor #

Gq excitatory.

• Ileum contraction, modulates circadian cycle, itching, sytemic Vasodilation, bronchoconstriction.
• Some random H1 antagonists are diphenhydramine, loratadine, cetirizine, fexofenadine, clemastine, rupatadine.
• Cocaine-Like Neurochemical Effects of Antihistaminic Medications
  • Intravenous diphenhydramine (1.0–3.0 mg/kg), (+)- and (−)-chlorpheniramine (1.0–5.6 mg/kg), but not triprolidine (1.0–3.0 mg/kg) elicited a cocaine-like pattern of stimulation of DA transmission, with larger effects in the NAc shell than core. The absence of stereospecific effects with chlorpheniramine enantiomers, along with the lack of an effect with triprolidine suggest that the effects on DA transmission were not related to H1 receptor antagonism.