1. A method of determining whether a substance is a ligand of a receptor, said method comprising:
obtaining a first population of cells comprising said receptor, wherein DNA encoding a marker indicative of the extent of cellular proliferation has been introduced into said first population of cells and wherein the amount of marker in said cells is influenced by the degree to which said receptor is active;
contacting said first population of cells with a test substance which is a potential ligand of said receptor;
comparing the amount of marker in said first population of cells which has been contacted with said test substance to the amount of marker in a second population of cells which has not been contacted with said test substance, said second population of cells comprising said receptor and DNA encoding said marker such that the extent of marker activity in said cells is influenced by the degree to which said receptor is active, wherein said test substance is a ligand of said receptor if the amount of marker in said first population of cells is significantly different than the amount of marker in said second population of cells.
2. The method of claim 1, wherein said comparing step is performed by measuring the amount of said marker in said first population of cells at a time after contacting said first population of cells with said test substance which is prior to the time at which foci resulting and by measuring the amount of said marker produced by said second population of cells at the same time as the amount of said marker in said test culture was measured.
3. The method of claim 1, wherein said comparing step is performed within two weeks of the day that said first population of cells was contacted with said substance.
4. The method of claim 1, wherein said comparing step is performed within 4 days of the day that said first population of cells was contacted with said substance.
5. The method of claim 1, further comprising contacting said first population of cells and said second population of cells with a substance known to be an agonist of said receptor.
6. The method of claim 1, further comprising contacting said first population of cells and said second population of cells with a substance known to be an antagonist of said receptor.
7. The method of claim 1, wherein said first population of cells and said second population of cells are obtained by introducing said DNA encoding said receptor and said DNA encoding said marker into a starting cell culture and dividing said starting cell culture into multiple aliquots.
8. The method of claim 1, wherein said receptor is the 5-HT2A receptor.
9. The method of claim 1, wherein said receptor has an elevated basal or constitutive receptor response and wherein said determining step comprises determining whether said substance inhibits said elevated basal or constitutive receptor response, wherein said substance is an inverse agonist of said receptor if said substance inhibits said elevated or constitutive receptor response of said receptor.
10. The method of claim 1, wherein said second population of cells comprises cells selected from the group consisting of:
(a) cells which do not comprise DNA encoding said marker;
(b) cells which do not comprise DNA encoding said receptor;
(c) cells which comprise DNA encoding said receptor but not DNA encoding said marker;
(d) cells which comprise DNA encoding said marker but not DNA encoding said receptor; and
(e) a combination of two or more of the cells recited in (a)-(d).
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A sheet media storage device comprising:
a storage pocket for storing sheet media; and
a feed roller for conveying the sheet media into the storage pocket;
wherein the storage pocket has a reverse feed prevention member that closes at least a part of a gap between the storage pocket and the feed roller.
2. The sheet media storage device described in claim 1, wherein:
the feed roller includes a main roller and a small roller part that is smaller in diameter than the main roller; and
the reverse feed prevention member extends from the storage pocket toward an outside surface of the small roller part.
3. The sheet media storage device described in claim 1, wherein:
the feed roller includes a main roller and a small roller part that is smaller in diameter than the main roller;
the reverse feed prevention member extends from the storage pocket toward an outside surface of the small roller part; and
a width of a distal end part of the reverse feed prevention member is substantially equal to or slightly smaller than a width of the small roller part.
4. The sheet media storage device described in claim 1, wherein:
the feed roller has a feed pin protruding radially from an outside surface of the feed roller.
5. The sheet media storage device described in claim 1, further comprising:
a pressure roller that pushes the sheet media to the feed roller.
6. A sheet media processing device comprising:
a sheet media transportation path for conveying sheet media; and
a sheet media storage device as described in claim 1 for storing the sheet media conveyed through the sheet media transportation path.
7. A sheet media storage device comprising:
a storage pocket for storing sheet media; and
a feed roller for conveying the sheet media into the storage pocket;
wherein the storage pocket has a reverse feed prevention guide surface spanning from an upstream end wall of the storage pocket to an end part of the feed roller.
8. The sheet media storage device described in claim 7, wherein:
the reverse feed prevention guide surface is positioned near a tangent to an outside surface of the feed roller.
9. The sheet media storage device described in claim 7, wherein:
the feed roller has a feed pin protruding radially from an outside surface of the feed roller.
10. The sheet media storage device described in claim 7, further comprising:
a pressure roller that pushes the sheet media to the feed roller.
11. A sheet media processing device comprising:
a sheet media transportation path for conveying sheet media; and
a sheet media storage device as described in claim 7 for storing the sheet media conveyed through the sheet media transportation path.
12. The sheet media storage device described in claim 2, wherein the reverse feed prevention member is a reverse feed prevention plate (53) that extends between an outside surface of the main roller (41) and an outside surface of the small roller (42).
13. The sheet media storage device described in claim 2, wherein a plurality of small roller parts (42) are disposed along an axial length of the feed roller (40).
14. The sheet media storage device described in claim 2, wherein the reverse feed prevention member is a reverse feed prevention plate (53) that is disposed perpendicular to a rotational axis of the feed roller (40).