Related Experiment Video

Updated: Jul 14, 2026

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development
07:56

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development

Published on: January 26, 2018

Histamine-induced contraction and relaxation of placental chorionic plate arteries

T A Mills1, M J Taggart, S L Greenwood

  • 1Maternal and Fetal Health Research Centre, Division of Human Development, The University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, UK.

Placenta
|July 3, 2007
PubMed

Studies of the human placental vasculature suggest a low resistance circulation. Using wire myography, endothelial-dependent relaxation of human chorionic plate arteries has been difficult to demonstrate with any consistency. However, histamine has been suggested to relax placental vessels in the perfused organ in vitro. Here we aimed to demonstrate endothelial-dependent relaxation to histamine under physiological conditions of stretch and oxygenation. Histamine administration to pre-contracted arteries induced a triphasic response; an initial contraction followed by a dilatation which stabilized to a significant relaxation compared to time control arteries. Relaxation was partially inhibited by blockers of endothelial-dependent relaxation pathways. The initial contraction was abolished by H(1)-receptor blockade with mepyramine. The relaxation was significantly reduced by H(2)-receptor blockade with famotidine but only abolished in the presence of both H(1)- and H(2)-receptor antagonists. In conclusion, histamine induced contraction and relaxation of human chorionic plate arteries. Our data suggest that contraction is mediated by activation of H(1)-receptors. Relaxation occurs directly, via activation of H(2)-receptors on vascular smooth muscle cells, and indirectly via H(1)-receptor stimulation of endothelial-dependent relaxation.

More Related Videos

Assessing Myogenic Response and Vasoactivity In Resistance Mesenteric Arteries Using Pressure Myography10:48

Assessing Myogenic Response and Vasoactivity In Resistance Mesenteric Arteries Using Pressure Myography

Published on: July 6, 2015

Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography07:51

Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography

Published on: September 22, 2011

Related Concept Videos

Vascular Spasm01:16

Vascular Spasm

The vascular phase, also known as vasospasm, is the initial stage of hemostasis, crucial for preventing excessive bleeding when a blood vessel is injured. After a vessel is cut, nerves in the damaged area trigger pain and other sensory impulses. Simultaneously, the smooth muscles in the vessel wall contract, resulting in a vascular spasm. This contraction reduces the vessel's diameter at the injury site, slowing or stopping blood loss through the vessel wall. Vascular spasms typically last for...
Nitric Oxide Signaling Pathway01:28

Nitric Oxide Signaling Pathway

Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...
Gonadal and Placental Hormones01:24

Gonadal and Placental Hormones

The gonads, namely the testes in males and the ovaries in females, are pivotal in producing gonadal hormones that orchestrate the intricate processes of sexual development and reproduction.
In males, testosterone is the primary gonadal androgen. It plays a central role in the maturation of male reproductive organs — the penis and testes. Additionally, testosterone is instrumental in the development of secondary sexual characteristics — a deep voice as well as facial and pubic hair growth — and...
Smooth Muscle Contraction01:25

Smooth Muscle Contraction

Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
Direct-Acting Cholinergic Agonists: Pharmacological Actions00:59

Direct-Acting Cholinergic Agonists: Pharmacological Actions

Direct-acting cholinergic agonists exert their pharmacological actions by mimicking the effects of acetylcholine on postsynaptic muscarinic receptors to generate parasympathetic responses. These agents elicit a range of physiological responses, including cardiovascular effects. For example, activation of muscarinic receptors induces bradycardia, decreased cardiac output, reduced peripheral resistance, and consequent hypotension. In the eye, stimulation of M3 receptors leads to smooth muscle...
Formation of the Platelet Plug01:22

Formation of the Platelet Plug

The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...