Due to government funding cuts, you have recently been appointed as head physiologist for the Centre for Disease Control, due to your unparalleled

Due to government funding cuts, you have recently been appointed as head physiologist for the Centre for Disease Control, due to your unparalleled physiology knowledge and willingness to work for minimum wage.

Billions of people served worldwide by the popular fast food chain McDowell's have all fallen ill due to a mysterious chemical being used in the beef. You are tasked with gathering as much information as possible about this chemical with a view to treating those affected.

Note: When people stop eating at McDowell's, they are no longer affected, but apparently that isn't an option, especially at 1:00am, nor is it an option to change the beef.

The chemical leads to a dramatically increased heart rate.

1. Which of the following experiments would be most appropriate to determine if the chemical is a steroid?

Inject the chemical into a rat and determine whether it causes sympathetic or parasympathetic activation.

Add the chemical to cultured cells and determine whether it's effect is immediate or delayed

Inject the chemical into a rat and determine if it only affects the heart, or if it affects the blood vessels as well.

Add the chemical to cultured cells and determine if the presence of adrenaline increases the effect of the chemical.

Through animal testing, you determine that the chemical increases heart rate by acting directly on the heart itself and affects autonomic nervous system signalling. It appears to have no direct effect on blood vessels. You have not determined if it is affecting other organ systems. Based on this information, the drug could be (select all that apply):

Acting on nicotinic receptors of both sympathetic and parasympathetic postganglionic neurons.

Acting on muscarinic receptors.

Acting on beta-1 adrenergic receptors.

Acting on beta-2 adrenergic receptors.

Acting on alpha-1 adrenergic receptors.

Acting on alpha-2 adrenergic receptors.

You are given the opportunity to interview the sufferers of the delicious beef scandal. Considering your answer to question 2, which of the following questions could help you determine which receptors are being affected by the chemical (select all that apply)?

Have you experienced any muscle weakness?

Have you had difficulty breathing?

Have your fingertips turned white (Generalised vasoconstriction)?

Have you experienced any erectile dysfunction?

Have you experienced an increased sensitivity to light?

You ask the patients all of the above questions (even though some may have been irrelevant), and they answer "no" to all of them. Judging by this, the chemical must be:
Activating nicotinic receptors.
Blocking nicotinic receptors.
Activating muscarinic receptors.
Blocking muscarinic receptors.
Activating beta-1 receptors.
Blocking beta-1 receptors.
Activating beta-2 receptors.
Blocking beta-2 receptors.
Activating alpha-1 receptors.
Blocking alpha-1 receptors.
Activating alpha-2 receptors.
Blocking alpha-2 receptors.

In an opportunistic move, McDowell's competitor, "Peckish Bill's" has begun putting a chemical in their special sauce which reduces the effect of the McDowell's chemical, slowing heart rate. The relationship between these two chemicals could be considered:

Permissive.

Synergistic.

Antagonistic.

im mainly stuck on question 4 and 5, but I'm also unsure if 2 and 3. This has even answered by someone but I don't agree/ don't understand how they came to their conclusion