Peristalis Movement

Peristalis Movement is a reflex response that is initiated when the gut wall is stretched by the contents of the lumen
A contractile ring appears around the gut and then moves forward
Peristalsis is an inherent property of many syncytial smooth muscle tubes;
The usual stimulus for intestinal peristalsis is distention of the gut.

BIOSYNTHESIS of Catecholamines

Overview
- biosynthesis of catecholamines is done in 3 (4) steps

TYROSINE
      | tyrosine hydroxylase
DOPA
      | DOPA decarboxylase
DOPAMINE
      | dopamine beta-hydroxylase
NORADRENALINE
      | phenylethanolamide N-methyltransferase (“PNMT”)
ADRENALINE
- , thus there are 3 (4) enzymes involved in catecholamine biosynthesis

ENZYME NAME

DESCRIPTION



TYROSINE HYDROXYLASE

- the rate-limiting step
- located in the cytoplasm of sympathetic postsynaptic neurons

DOPA DECARBOXYLASE

DOPAMINE BETA-HYDROXYLASE
PNMT

- general enzyme located in the cytoplasm of most cells
- catalyses decarboxylation of aromatic amino acids
- located in the synaptic vesicles of postsynaptic sympathetic nerve terminals
- located in the a-cells of the adrenal medulla

Relevant Drugs
- 3 types

DRUG NAME

DESCRIPTION



ALPHA-METHYLTYROSINE

METHYLDOPA

General information
- a tyrosine hydroxylase inhibitor
- inhibits tyrosine hydroxylase, thus causing inhibition of catecholamine synthesis
Clinical use
- treatment of pheochromocytoma (a catecholamine-
producing adrenal medullary tumor)
Side effects
- hypotension (due to vasodilation)
- drowsiness
General information
- a central DOPA decarboxylase inhibitor (may cross the blood-brain barrier)
- alternate substrate for DOPA decarboxylase , thus displacing DOPA from the active site of DOPA decarboxylase and following inhibition of catecholamine synthesis
- is converted by DOPA decarboxylase to methylnoradrenalin (a selective alpha-2 agonist, see 19)
Clinical use
- treatment of hypertension during pregnancy (by
inhibition of the sympathetic nuclei of the brainstem)
Side effects
- same as alpha-methyltyrosine (see above)

CARBIDOPA
- impotency
- hypersensitivity reactions
General information
- a peripheral DOPA decarboxylase inhibitor (may not
pass the blood-brain barrier)
Clinical use
- treatment of parkinson’s disease (by inhibition of the
use of DOPA for catecholamine synthesis in
peripheral neurons, thus freeing it for restorement of
 the dopaminergic pathways of the brain
 

Japan’s Earth Quake and Tsunami is the costliest Natural disaster!!!

The Japanese government on Wednesday estimated the direct damage from a deadly earthquake and tsunami that struck the country's northeast this month at as much as $310 billion, making it the world's expensive natural disaster.

The first official damage estimates will serve to map out disaster relief plans and emergency budgets to fund recovery costs.

Tokyo said the estimate covered damage to roads, homes, factories and other infrastructure, and eclipses the losses incurred by other natural disasters such as the 1995 Kobe quake and Hurricane Katrina in 2005.

The figure could go even higher, as the estimate does not include losses in economic activity from planned power outages or the broader impact of a crisis at a stricken nuclear power plant in Fukushima, which economists say pose the biggest risks to the economy.

"The impact from the planned power outages is likely to be significant," Fumihira Nishizaki, director of macroeconomic analysis at the Cabinet Office told reporters.

The upper end of the 16-25 trillion yen ($197-308 billion) estimate range would amount to about 6 percent of Japan's gross domestic product.

"This quake will cause the condition of Japan's economy and output to be severe," Bank of Japan Governor Masaaki Shirakawa told a parliamentary committee.

Speaking separately, central bank board member Ryuzo Miyao repeated the bank's pledge to take appropriate policy action if needed to support the world's third-largest economy.

"We need to be mindful that the quake's negative impact on the economy, at least on the supply side, may be bigger than the Kobe quake 16 years ago, and be prolonged," he added.

In its initial response to the disaster, the central bank doubled the funds earmarked for purchases of a range of assets and started pumping record amounts of cash into the money market to prevent it from seizing up.

It later followed up by joining forces with other G7 central banks in a rare coordinated move to keep a rallying yen from inflicting further damage to the economy.